diff --git a/app/controllers/concerns/integrations/params.rb b/app/controllers/concerns/integrations/params.rb
index 62585ab95af7b19a2b31a356b99b637617bb4fa4..201fb1dc83f2c913bb233cd3f034ca9a39f4e27e 100644
--- a/app/controllers/concerns/integrations/params.rb
+++ b/app/controllers/concerns/integrations/params.rb
@@ -9,6 +9,7 @@ module Params
       :add_pusher,
       :alert_events,
       :api_key,
+      :api_token,
       :api_url,
       :bamboo_url,
       :branches_to_be_notified,
@@ -74,7 +75,8 @@ module Params
       :url,
       :user_key,
       :username,
-      :webhook
+      :webhook,
+      :zentao_product_xid
     ].freeze
 
     def integration_params
diff --git a/app/helpers/integrations_helper.rb b/app/helpers/integrations_helper.rb
index 8819aa9e9cc1b2ba365c99d2bd01f16028209a15..bb4a7fef6be1dc57b331810a86e0187d4dc9801d 100644
--- a/app/helpers/integrations_helper.rb
+++ b/app/helpers/integrations_helper.rb
@@ -132,6 +132,20 @@ def jira_issue_breadcrumb_link(issue_reference)
     end
   end
 
+  def zentao_issue_breadcrumb_link(issue)
+    link_to issue[:web_url], { target: '_blank', rel: 'noopener noreferrer', class: 'gl-display-flex gl-align-items-center gl-white-space-nowrap' } do
+      icon = image_tag image_path('logos/zentao.svg'), width: 15, height: 15, class: 'gl-mr-2'
+      [icon, html_escape(issue[:id])].join.html_safe
+    end
+  end
+
+  def zentao_issues_show_data
+    {
+      issues_show_path: project_integrations_zentao_issue_path(@project, params[:id], format: :json),
+      issues_list_path: project_integrations_zentao_issues_path(@project)
+    }
+  end
+
   extend self
 
   private
diff --git a/app/models/integration.rb b/app/models/integration.rb
index 158764bb783e9f20659047b548e55ba79991f891..4dd3e1a1785831e69b854f162868d4d27aed0279 100644
--- a/app/models/integration.rb
+++ b/app/models/integration.rb
@@ -14,7 +14,7 @@ class Integration < ApplicationRecord
     asana assembla bamboo bugzilla buildkite campfire confluence custom_issue_tracker datadog discord
     drone_ci emails_on_push ewm external_wiki flowdock hangouts_chat irker jira
     mattermost mattermost_slash_commands microsoft_teams packagist pipelines_email
-    pivotaltracker prometheus pushover redmine slack slack_slash_commands teamcity unify_circuit webex_teams youtrack
+    pivotaltracker prometheus pushover redmine slack slack_slash_commands teamcity unify_circuit webex_teams youtrack zentao
   ].freeze
 
   PROJECT_SPECIFIC_INTEGRATION_NAMES = %w[
diff --git a/app/models/integrations/zentao.rb b/app/models/integrations/zentao.rb
index 68c02f54c61246ae52edc3a152e2f8d4870093ae..2b3e5b6001fa8fa2ec02ae080ad2271c7ce2381f 100644
--- a/app/models/integrations/zentao.rb
+++ b/app/models/integrations/zentao.rb
@@ -9,16 +9,25 @@ class Zentao < Integration
     validates :api_token, presence: true, if: :activated?
     validates :zentao_product_xid, presence: true, if: :activated?
 
+    def self.feature_flag_enabled?(project)
+      Feature.enabled?(:zentao_issues_integration, project)
+    end
+
+    # License Level: EEP_FEATURES
+    def self.issues_license_available?(project)
+      project&.licensed_feature_available?(:zentao_issues_integration)
+    end
+
     def data_fields
       zentao_tracker_data || self.build_zentao_tracker_data
     end
 
     def title
-      self.class.name.demodulize
+      'ZenTao'
     end
 
     def description
-      s_("ZentaoIntegration|Use Zentao as this project's issue tracker.")
+      s_("ZentaoIntegration|Use ZenTao as this project's issue tracker.")
     end
 
     def self.to_param
@@ -42,28 +51,28 @@ def fields
         {
           type: 'text',
           name: 'url',
-          title: s_('ZentaoIntegration|Zentao Web URL'),
+          title: s_('ZentaoIntegration|ZenTao Web URL'),
           placeholder: 'https://www.zentao.net',
-          help: s_('ZentaoIntegration|Base URL of the Zentao instance.'),
+          help: s_('ZentaoIntegration|Base URL of the ZenTao instance.'),
           required: true
         },
         {
           type: 'text',
           name: 'api_url',
-          title: s_('ZentaoIntegration|Zentao API URL (optional)'),
+          title: s_('ZentaoIntegration|ZenTao API URL (optional)'),
           help: s_('ZentaoIntegration|If different from Web URL.')
         },
         {
           type: 'password',
           name: 'api_token',
-          title: s_('ZentaoIntegration|Zentao API token'),
+          title: s_('ZentaoIntegration|ZenTao API token'),
           non_empty_password_title: s_('ZentaoIntegration|Enter API token'),
           required: true
         },
         {
           type: 'text',
           name: 'zentao_product_xid',
-          title: s_('ZentaoIntegration|Zentao Product ID'),
+          title: s_('ZentaoIntegration|ZenTao Product ID'),
           required: true
         }
       ]
diff --git a/app/models/project.rb b/app/models/project.rb
index 6eb19b4462cfbbdbd018db55d6425dd01d1e2334..b827f48e706eb6cb0c2540ff60bda164765c51d9 100644
--- a/app/models/project.rb
+++ b/app/models/project.rb
@@ -1453,7 +1453,10 @@ def find_or_initialize_integrations
   end
 
   def disabled_integrations
-    [:zentao]
+    disabled_integrations = []
+    disabled_integrations << :zentao unless ::Integrations::Zentao.feature_flag_enabled?(self)
+
+    disabled_integrations
   end
 
   def find_or_initialize_integration(name)
diff --git a/config/feature_flags/development/zentao_issues_integration.yml b/config/feature_flags/development/zentao_issues_integration.yml
new file mode 100644
index 0000000000000000000000000000000000000000..150340874cb54aebcc87b3c2b3eee3b595516b9c
--- /dev/null
+++ b/config/feature_flags/development/zentao_issues_integration.yml
@@ -0,0 +1,8 @@
+---
+name: zentao_issues_integration
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/69602
+rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/338775
+milestone: '14.4'
+type: development
+group: group::integrations
+default_enabled: false
diff --git a/config/metrics/counts_all/20210730011801_projects_zentao_active.yml b/config/metrics/counts_all/20210730011801_projects_zentao_active.yml
new file mode 100644
index 0000000000000000000000000000000000000000..8a9c3f969a07cbbaa80a33bb2f1ad747bbcd4db5
--- /dev/null
+++ b/config/metrics/counts_all/20210730011801_projects_zentao_active.yml
@@ -0,0 +1,22 @@
+---
+key_path: counts.projects_zentao_active
+name: count_all_projects_zentao_active
+description: Count of projects with active Zentao integrations
+product_section: dev
+product_stage: ecosystem
+product_group: group::integrations
+product_category: integrations
+value_type: number
+status: active
+milestone: "14.4"
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/issues/338178
+time_frame: all
+data_source: database
+data_category: Operational
+distribution:
+- ce
+- ee
+tier:
+- free
+- premium
+- ultimate
diff --git a/config/metrics/counts_all/20210730011802_groups_zentao_active.yml b/config/metrics/counts_all/20210730011802_groups_zentao_active.yml
new file mode 100644
index 0000000000000000000000000000000000000000..c8a1dfbbdd22fd304975010dabdeb93e6fa1d316
--- /dev/null
+++ b/config/metrics/counts_all/20210730011802_groups_zentao_active.yml
@@ -0,0 +1,22 @@
+---
+key_path: counts.groups_zentao_active
+name: count_all_groups_zentao_active
+description: Count of groups with active Zentao integrations
+product_section: dev
+product_stage: ecosystem
+product_group: group::integrations
+product_category: integrations
+value_type: number
+status: active
+milestone: "14.4"
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/issues/338178
+time_frame: all
+data_source: database
+data_category: Operational
+distribution:
+- ce
+- ee
+tier:
+- free
+- premium
+- ultimate
diff --git a/config/metrics/counts_all/20210730011804_instances_zentao_active.yml b/config/metrics/counts_all/20210730011804_instances_zentao_active.yml
new file mode 100644
index 0000000000000000000000000000000000000000..b1c2a9d8b13e5be6bc402a84b6ba2f45eb697fde
--- /dev/null
+++ b/config/metrics/counts_all/20210730011804_instances_zentao_active.yml
@@ -0,0 +1,22 @@
+---
+key_path: counts.instances_zentao_active
+name: count_all_instances_zentao_active
+description: Count of instances with active Zentao integrations
+product_section: dev
+product_stage: ecosystem
+product_group: group::integrations
+product_category: integrations
+value_type: number
+status: active
+milestone: "14.4"
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/issues/338178
+time_frame: all
+data_source: database
+data_category: Operational
+distribution:
+- ce
+- ee
+tier:
+- free
+- premium
+- ultimate
diff --git a/config/metrics/counts_all/20210730011805_projects_inheriting_zentao_active.yml b/config/metrics/counts_all/20210730011805_projects_inheriting_zentao_active.yml
new file mode 100644
index 0000000000000000000000000000000000000000..34c48ada0ee71e61f477630db212a920f2abf6ca
--- /dev/null
+++ b/config/metrics/counts_all/20210730011805_projects_inheriting_zentao_active.yml
@@ -0,0 +1,22 @@
+---
+key_path: counts.projects_inheriting_zentao_active
+name: count_all_projects_inheriting_zentao_active
+description: Count of projects that inherit active Zentao integrations
+product_section: dev
+product_stage: ecosystem
+product_group: group::integrations
+product_category: integrations
+value_type: number
+status: active
+milestone: "14.4"
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/issues/338178
+time_frame: all
+data_source: database
+data_category: Operational
+distribution:
+- ce
+- ee
+tier:
+- free
+- premium
+- ultimate
diff --git a/config/metrics/counts_all/20210730011806_groups_inheriting_zentao_active.yml b/config/metrics/counts_all/20210730011806_groups_inheriting_zentao_active.yml
new file mode 100644
index 0000000000000000000000000000000000000000..4d374db026e80d20b78aaa9d4accf0bd364c2e89
--- /dev/null
+++ b/config/metrics/counts_all/20210730011806_groups_inheriting_zentao_active.yml
@@ -0,0 +1,22 @@
+---
+key_path: counts.groups_inheriting_zentao_active
+name: count_all_groups_inheriting_zentao_active
+description: Count of groups that inherit active Zentao integrations
+product_section: dev
+product_stage: ecosystem
+product_group: group::integrations
+product_category: integrations
+value_type: number
+status: active
+milestone: "14.4"
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/issues/338178
+time_frame: all
+data_source: database
+data_category: Operational
+distribution:
+- ce
+- ee
+tier:
+- free
+- premium
+- ultimate
diff --git a/doc/api/graphql/reference/index.md b/doc/api/graphql/reference/index.md
index 17d62ea19ad8a2b0aeaca791608d834e0776da87..c228d8ae205a308e7237ed40ccb8d9a9b2c0660c 100644
--- a/doc/api/graphql/reference/index.md
+++ b/doc/api/graphql/reference/index.md
@@ -16578,6 +16578,7 @@ State of a Sentry error.
 | <a id="servicetypeunify_circuit_service"></a>`UNIFY_CIRCUIT_SERVICE` | UnifyCircuitService type. |
 | <a id="servicetypewebex_teams_service"></a>`WEBEX_TEAMS_SERVICE` | WebexTeamsService type. |
 | <a id="servicetypeyoutrack_service"></a>`YOUTRACK_SERVICE` | YoutrackService type. |
+| <a id="servicetypezentao_service"></a>`ZENTAO_SERVICE` | ZentaoService type. |
 
 ### `SharedRunnersSetting`
 
diff --git a/ee/app/controllers/projects/integrations/zentao/issues_controller.rb b/ee/app/controllers/projects/integrations/zentao/issues_controller.rb
new file mode 100644
index 0000000000000000000000000000000000000000..0d40c46f793d976d8ad92a9b7f5a4b123ee27386
--- /dev/null
+++ b/ee/app/controllers/projects/integrations/zentao/issues_controller.rb
@@ -0,0 +1,70 @@
+# frozen_string_literal: true
+
+module Projects
+  module Integrations
+    module Zentao
+      class IssuesController < Projects::ApplicationController
+        include RecordUserLastActivity
+
+        before_action :check_feature_enabled!
+
+        rescue_from ::Gitlab::Zentao::Client::Error, with: :render_error
+
+        feature_category :integrations
+
+        def index
+          respond_to do |format|
+            format.html
+            format.json do
+              render json: issues_json
+            end
+          end
+        end
+
+        def show
+          @issue_json = issue_json
+          respond_to do |format|
+            format.html
+            format.json do
+              render json: @issue_json
+            end
+          end
+        end
+
+        private
+
+        def query_params
+          params.permit(:id, :page, :limit, :search, :sort, :state, :labels)
+        end
+
+        def query
+          ::Gitlab::Zentao::Query.new(project.zentao_integration, query_params)
+        end
+
+        def issue_json
+          ::Integrations::ZentaoSerializers::IssueDetailSerializer.new
+                                                                  .represent(query.issue, project: project)
+        end
+
+        def issues_json
+          ::Integrations::ZentaoSerializers::IssueSerializer.new
+                                                            .with_pagination(request, response)
+                                                            .represent(query.issues, project: project)
+        end
+
+        def check_feature_enabled!
+          return render_404 unless ::Integrations::Zentao.feature_flag_enabled?(project)
+
+          return render_404 unless ::Integrations::Zentao.issues_license_available?(project) && project.zentao_integration&.active?
+        end
+
+        def render_error(exception)
+          log_exception(exception)
+
+          render json: { errors: [s_('ZentaoIntegration|An error occurred while requesting data from the ZenTao service.')] },
+            status: :bad_request
+        end
+      end
+    end
+  end
+end
diff --git a/ee/app/models/ee/project.rb b/ee/app/models/ee/project.rb
index d4ac2be5e98217b99355bb4ca7421e72cb0078bf..1f68b5aa44e733b882db00fee837c17efd097c2b 100644
--- a/ee/app/models/ee/project.rb
+++ b/ee/app/models/ee/project.rb
@@ -404,10 +404,6 @@ def jira_issues_integration_available?
       feature_available?(:jira_issues_integration)
     end
 
-    def zentao_issues_integration_available?
-      feature_available?(:zentao_issues_integration)
-    end
-
     def multiple_approval_rules_available?
       feature_available?(:multiple_approval_rules)
     end
diff --git a/ee/app/serializers/integrations/zentao_serializers/issue_detail_entity.rb b/ee/app/serializers/integrations/zentao_serializers/issue_detail_entity.rb
new file mode 100644
index 0000000000000000000000000000000000000000..0f40bf87a95037be8e82a3b525642e9deb448229
--- /dev/null
+++ b/ee/app/serializers/integrations/zentao_serializers/issue_detail_entity.rb
@@ -0,0 +1,29 @@
+# frozen_string_literal: true
+
+module Integrations
+  module ZentaoSerializers
+    class IssueDetailEntity < IssueEntity
+      expose :description_html do |item|
+        sanitize(item['desc'])
+      end
+
+      expose :comments do |item|
+        item['comments'].map do |comment|
+          {
+            id: comment['id']&.to_i,
+            created_at: comment['date']&.to_datetime&.utc,
+            body_html: body_html(comment),
+            author: user_info(comment['actor'])
+          }
+        end
+      end
+
+      private
+
+      def body_html(comment)
+        content = [comment['title'], comment['body_html']].join('<br>')
+        sanitize(content)
+      end
+    end
+  end
+end
diff --git a/ee/app/serializers/integrations/zentao_serializers/issue_detail_serializer.rb b/ee/app/serializers/integrations/zentao_serializers/issue_detail_serializer.rb
new file mode 100644
index 0000000000000000000000000000000000000000..72bd7e41b080e3e387daeb97c34ebef1c02555fe
--- /dev/null
+++ b/ee/app/serializers/integrations/zentao_serializers/issue_detail_serializer.rb
@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+module Integrations
+  module ZentaoSerializers
+    class IssueDetailSerializer < BaseSerializer
+      entity ::Integrations::ZentaoSerializers::IssueDetailEntity
+    end
+  end
+end
diff --git a/ee/app/serializers/integrations/zentao_serializers/issue_entity.rb b/ee/app/serializers/integrations/zentao_serializers/issue_entity.rb
new file mode 100644
index 0000000000000000000000000000000000000000..266af532362dfb5234cc6bad4511085a2b6a6de4
--- /dev/null
+++ b/ee/app/serializers/integrations/zentao_serializers/issue_entity.rb
@@ -0,0 +1,89 @@
+# frozen_string_literal: true
+
+module Integrations
+  module ZentaoSerializers
+    class IssueEntity < Grape::Entity
+      include ActionView::Helpers::SanitizeHelper
+      include RequestAwareEntity
+
+      expose :id do |item|
+        sanitize(item['id'])
+      end
+
+      expose :project_id do |item|
+        project.id
+      end
+
+      expose :title do |item|
+        sanitize(item['title'])
+      end
+
+      expose :created_at do |item|
+        item['openedDate']&.to_datetime&.utc
+      end
+
+      expose :updated_at do |item|
+        item['lastEditedDate']&.to_datetime&.utc
+      end
+
+      expose :closed_at do |item|
+        item['lastEditedDate']&.to_datetime&.utc if item['status'] == 'closed'
+      end
+
+      expose :status do |item|
+        sanitize(item['status'])
+      end
+
+      expose :state do |item|
+        sanitize(item['status'])
+      end
+
+      expose :labels do |item|
+        item['labels'].compact.map do |label|
+          name = sanitize(label)
+          {
+            id: name,
+            title: name,
+            name: name,
+            color: '#0052CC',
+            text_color: '#FFFFFF'
+          }
+        end
+      end
+
+      expose :author do |item|
+        user_info(item['openedBy'])
+      end
+
+      expose :assignees do |item|
+        item['assignedTo'].compact.map do |user|
+          user_info(user)
+        end
+      end
+
+      expose :web_url do |item|
+        item['url']
+      end
+
+      expose :gitlab_web_url do |item|
+        project_integrations_zentao_issue_path(project, item['id'])
+      end
+
+      private
+
+      def project
+        @project ||= options[:project]
+      end
+
+      def user_info(user)
+        return {} unless user.present?
+
+        {
+          "name": sanitize(user['realname'].presence || user['account']),
+          "web_url": user['url'],
+          "avatar_url": user['avatar']
+        }
+      end
+    end
+  end
+end
diff --git a/ee/app/serializers/integrations/zentao_serializers/issue_serializer.rb b/ee/app/serializers/integrations/zentao_serializers/issue_serializer.rb
new file mode 100644
index 0000000000000000000000000000000000000000..064833554f290a0262c7ef622994fe88200af690
--- /dev/null
+++ b/ee/app/serializers/integrations/zentao_serializers/issue_serializer.rb
@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+module Integrations
+  module ZentaoSerializers
+    class IssueSerializer < BaseSerializer
+      include WithPagination
+
+      entity ::Integrations::ZentaoSerializers::IssueEntity
+    end
+  end
+end
diff --git a/ee/app/views/projects/integrations/zentao/issues/index.html.haml b/ee/app/views/projects/integrations/zentao/issues/index.html.haml
new file mode 100644
index 0000000000000000000000000000000000000000..16420a300a0cd8d7cda50f28295b2c7e67f8fe79
--- /dev/null
+++ b/ee/app/views/projects/integrations/zentao/issues/index.html.haml
@@ -0,0 +1,10 @@
+- page_title _('ZentaoIntegration|Zentao issues')
+- add_page_specific_style 'page_bundles/issues_list'
+
+.js-zentao-issues-list{ data: { issues_fetch_path: project_integrations_zentao_issues_path(@project, format: :json),
+                                page: params[:page],
+                                initial_state: params[:state],
+                                initial_sort_by: params[:sort],
+                                project_full_path: @project.full_path,
+                                issue_create_url: @project.zentao_integration.url,
+                                empty_state_path: image_path('illustrations/issues.svg') } }
diff --git a/ee/app/views/projects/integrations/zentao/issues/show.html.haml b/ee/app/views/projects/integrations/zentao/issues/show.html.haml
new file mode 100644
index 0000000000000000000000000000000000000000..057a2fd8f26413d2459da6504f62ebe0ab1bce0d
--- /dev/null
+++ b/ee/app/views/projects/integrations/zentao/issues/show.html.haml
@@ -0,0 +1,5 @@
+- add_to_breadcrumbs _('Zentao issues'), project_integrations_zentao_issues_path(@project)
+- breadcrumb_title zentao_issue_breadcrumb_link(@issue_json)
+- page_title html_escape(@issue_json[:title])
+
+.js-zentao-issues-show-app{ data: zentao_issues_show_data }
diff --git a/ee/config/routes/project.rb b/ee/config/routes/project.rb
index 5ba33247a6c8df76cb3bd122b3d785ced8978a73..f8ca182ad1d4dcb8afc49589cded4586ed7f49d3 100644
--- a/ee/config/routes/project.rb
+++ b/ee/config/routes/project.rb
@@ -119,6 +119,10 @@
               end
             end
           end
+
+          namespace :zentao do
+            resources :issues, only: [:index, :show]
+          end
         end
 
         # Added for backward compatibility with https://gitlab.com/gitlab-org/gitlab/-/merge_requests/39543
diff --git a/ee/lib/ee/sidebars/projects/menus/zentao_menu.rb b/ee/lib/ee/sidebars/projects/menus/zentao_menu.rb
new file mode 100644
index 0000000000000000000000000000000000000000..049cbc063d1cf2ef4bb54bb637d81e210de9f0d6
--- /dev/null
+++ b/ee/lib/ee/sidebars/projects/menus/zentao_menu.rb
@@ -0,0 +1,41 @@
+# frozen_string_literal: true
+
+module EE
+  module Sidebars
+    module Projects
+      module Menus
+        module ZentaoMenu
+          extend ::Gitlab::Utils::Override
+
+          override :link
+          def link
+            return super unless feature_available?
+
+            project_integrations_zentao_issues_path(context.project)
+          end
+
+          override :add_items
+          def add_items
+            add_item(issue_list_menu_item) if feature_available?
+            super
+          end
+
+          private
+
+          def feature_available?
+            ::Integrations::Zentao.issues_license_available?(context.project)
+          end
+
+          def issue_list_menu_item
+            ::Sidebars::MenuItem.new(
+              title: s_('ZentaoIntegration|Issue list'),
+              link: project_integrations_zentao_issues_path(context.project),
+              active_routes: { controller: 'projects/integrations/zentao/issues' },
+              item_id: :issue_list
+            )
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/ee/spec/controllers/projects/integrations/zentao/issues_controller_spec.rb b/ee/spec/controllers/projects/integrations/zentao/issues_controller_spec.rb
new file mode 100644
index 0000000000000000000000000000000000000000..f60bd94ee8c15332f31789c9c0690be64922eb81
--- /dev/null
+++ b/ee/spec/controllers/projects/integrations/zentao/issues_controller_spec.rb
@@ -0,0 +1,127 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Projects::Integrations::Zentao::IssuesController do
+  let_it_be(:project) { create(:project) }
+  let_it_be(:user) { create(:user, developer_projects: [project]) }
+  let_it_be(:zentao_integration) { create(:zentao_integration, project: project) }
+
+  before do
+    stub_licensed_features(zentao_issues_integration: true)
+    sign_in(user)
+  end
+
+  describe 'GET #index' do
+    context 'when zentao_issues_integration licensed feature is not available' do
+      before do
+        stub_licensed_features(zentao_issues_integration: false)
+      end
+
+      it 'returns 404 status' do
+        get :index, params: { namespace_id: project.namespace, project_id: project }
+
+        expect(response).to have_gitlab_http_status(:not_found)
+      end
+    end
+
+    it_behaves_like 'unauthorized when external service denies access' do
+      subject { get :index, params: { namespace_id: project.namespace, project_id: project } }
+    end
+
+    it 'renders the "index" template' do
+      get :index, params: { namespace_id: project.namespace, project_id: project }
+
+      expect(response).to have_gitlab_http_status(:ok)
+      expect(response).to render_template(:index)
+    end
+
+    context 'json request' do
+      let(:zentao_issue) { [] }
+
+      it 'returns a list of serialized zentao issues' do
+        expect_next_instance_of(::Gitlab::Zentao::Query) do |query|
+          expect(query).to receive(:issues).and_return(zentao_issue)
+        end
+
+        expect_next_instance_of(Integrations::ZentaoSerializers::IssueSerializer) do |serializer|
+          expect(serializer).to receive(:represent).with(zentao_issue, project: project)
+        end
+
+        get :index, params: { namespace_id: project.namespace, project_id: project }, format: :json
+      end
+
+      it 'renders bad request for Error' do
+        expect_next_instance_of(::Gitlab::Zentao::Query) do |query|
+          expect(query).to receive(:issues).and_raise(::Gitlab::Zentao::Client::Error)
+        end
+        expect(Gitlab::ErrorTracking).to receive(:track_exception)
+
+        get :index, params: { namespace_id: project.namespace, project_id: project }, format: :json
+
+        expect(response).to have_gitlab_http_status(:bad_request)
+        expect(json_response['errors']).to match_array [s_('ZentaoIntegration|An error occurred while requesting data from the ZenTao service.')]
+      end
+    end
+  end
+
+  describe 'GET #show' do
+    context 'when zentao_issues_integration licensed feature is not available' do
+      before do
+        stub_licensed_features(zentao_issues_integration: false)
+      end
+
+      it 'returns 404 status' do
+        get :show, params: { namespace_id: project.namespace, project_id: project, id: 1 }
+
+        expect(response).to have_gitlab_http_status(:not_found)
+      end
+    end
+
+    context 'when zentao_issues_integration licensed feature is available' do
+      let(:zentao_issue) { { 'from' => 'zentao' } }
+      let(:issue_json) { { 'from' => 'backend' } }
+
+      before do
+        stub_licensed_features(zentao_issues_integration: true)
+
+        expect_next_instance_of(::Gitlab::Zentao::Query) do |query|
+          allow(query).to receive(:issue).and_return(zentao_issue)
+        end
+
+        allow_next_instance_of(Integrations::ZentaoSerializers::IssueDetailSerializer) do |serializer|
+          allow(serializer).to receive(:represent).with(zentao_issue, project: project).and_return(issue_json)
+        end
+      end
+
+      it 'renders `show` template' do
+        get :show, params: { namespace_id: project.namespace, project_id: project, id: 'story-1' }
+
+        expect(assigns(:issue_json)).to eq(issue_json)
+        expect(response).to have_gitlab_http_status(:ok)
+        expect(response).to render_template(:show)
+      end
+
+      it 'returns JSON response' do
+        get :show, params: { namespace_id: project.namespace, project_id: project, id: 'story-1', format: :json }
+
+        expect(json_response).to eq(issue_json)
+      end
+
+      context 'when the JSON fetched from ZenTao contains HTML' do
+        let(:payload) { "<script>alert('XSS')</script>" }
+        let(:issue_json) { { id: payload, title: payload, status: payload, labels: [payload] } }
+
+        render_views
+
+        it 'escapes the HTML in issue' do
+          get :show, params: { namespace_id: project.namespace, project_id: project, id: 'story-1' }
+
+          expect(response).to have_gitlab_http_status(:ok)
+          expect(response.body).not_to include(payload)
+          expect(response.body).to include(html_escape(payload))
+        end
+      end
+    end
+  end
+end
diff --git a/ee/spec/lib/ee/sidebars/projects/menus/zentao_menu_spec.rb b/ee/spec/lib/ee/sidebars/projects/menus/zentao_menu_spec.rb
new file mode 100644
index 0000000000000000000000000000000000000000..37b9a5347b9502b460d969dcd066bfbe9fe747da
--- /dev/null
+++ b/ee/spec/lib/ee/sidebars/projects/menus/zentao_menu_spec.rb
@@ -0,0 +1,54 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Sidebars::Projects::Menus::ZentaoMenu do
+  let(:project) { create(:project, has_external_issue_tracker: true) }
+  let(:user) { project.owner }
+  let(:context) { Sidebars::Projects::Context.new(current_user: user, container: project) }
+  let(:zentao_integration) { create(:zentao_integration, project: project) }
+
+  subject { described_class.new(context) }
+
+  describe 'when feature is not licensed' do
+    before do
+      stub_licensed_features(zentao_issues_integration: false)
+    end
+
+    it_behaves_like 'ZenTao menu with CE version'
+  end
+
+  describe 'when feature is licensed' do
+    before do
+      stub_licensed_features(zentao_issues_integration: true)
+    end
+
+    context 'when issues integration is disabled' do
+      before do
+        zentao_integration.update!(active: false)
+      end
+
+      it 'returns false' do
+        expect(subject.render?).to eq false
+      end
+    end
+
+    context 'when issues integration is enabled' do
+      before do
+        zentao_integration.update!(active: true)
+      end
+
+      it 'returns true' do
+        expect(subject.render?).to eq true
+      end
+
+      it 'renders menu link' do
+        expect(subject.link).to include('/-/integrations/zentao/issues')
+      end
+
+      it 'contains issue list and open ZenTao menu items' do
+        expect(subject.renderable_items.map(&:item_id)).to match_array [:issue_list, :open_zentao]
+      end
+    end
+  end
+end
diff --git a/lib/api/helpers/integrations_helpers.rb b/lib/api/helpers/integrations_helpers.rb
index e0ef9099104e4d72ac05fe713cfebf65f4ec2d11..7ae46abd0971c51630fbfd84d3b7cd6424cd7b9a 100644
--- a/lib/api/helpers/integrations_helpers.rb
+++ b/lib/api/helpers/integrations_helpers.rb
@@ -254,7 +254,7 @@ def self.integrations
               type: Boolean,
               desc: 'DEPRECATED: This parameter has no effect since SSL verification will always be enabled'
             }
-        ],
+          ],
           'campfire' => [
             {
               required: true,
@@ -768,7 +768,33 @@ def self.integrations
               desc: 'The Webex Teams webhook. For example, https://api.ciscospark.com/v1/webhooks/incoming/...'
             },
             chat_notification_events
-          ].flatten
+          ].flatten,
+          'zentao' => [
+            {
+              required: true,
+              name: :url,
+              type: String,
+              desc: 'The base URL to the ZenTao instance web interface which is being linked to this GitLab project. For example, https://www.zentao.net'
+            },
+            {
+              required: false,
+              name: :api_url,
+              type: String,
+              desc: 'The base URL to the ZenTao instance API. Web URL value will be used if not set. For example, https://www.zentao.net'
+            },
+            {
+              required: true,
+              name: :api_token,
+              type: String,
+              desc: 'The API token created from ZenTao dashboard'
+            },
+            {
+              required: true,
+              name: :zentao_product_xid,
+              type: String,
+              desc: 'The product ID of ZenTao project'
+            }
+          ]
         }
       end
 
@@ -805,7 +831,8 @@ def self.integration_classes
           ::Integrations::Slack,
           ::Integrations::SlackSlashCommands,
           ::Integrations::Teamcity,
-          ::Integrations::Youtrack
+          ::Integrations::Youtrack,
+          ::Integrations::Zentao
         ]
       end
 
diff --git a/lib/gitlab/zentao/client.rb b/lib/gitlab/zentao/client.rb
index bdfa4b3a308e853188261641dab898abf66013af..e22d57faeca425a1e8388bb07f65105bf3cfe14d 100644
--- a/lib/gitlab/zentao/client.rb
+++ b/lib/gitlab/zentao/client.rb
@@ -15,10 +15,8 @@ def initialize(integration)
       end
 
       def ping
-        response = fetch_product(zentao_product_xid)
-
+        response = fetch_product(zentao_product_xid) rescue {}
         active = response.fetch('deleted') == '0' rescue false
-
         if active
           { success: true }
         else
@@ -31,25 +29,30 @@ def fetch_product(product_id)
       end
 
       def fetch_issues(params = {})
-        get("products/#{zentao_product_xid}/issues",
-            params.reverse_merge(page: 1, limit: 20))
+        get("products/#{zentao_product_xid}/issues", params)
       end
 
       def fetch_issue(issue_id)
+        raise Gitlab::Zentao::Client::Error unless issue_id_pattern.match(issue_id)
+
         get("issues/#{issue_id}")
       end
 
       private
 
+      def issue_id_pattern
+        /\A\S+-\d+\z/
+      end
+
       def get(path, params = {})
         options = { headers: headers, query: params }
         response = Gitlab::HTTP.get(url(path), options)
 
-        return {} unless response.success?
+        raise Gitlab::Zentao::Client::Error unless response.success?
 
         Gitlab::Json.parse(response.body)
       rescue JSON::ParserError
-        {}
+        raise Gitlab::Zentao::Client::Error
       end
 
       def url(path)
diff --git a/lib/gitlab/zentao/query.rb b/lib/gitlab/zentao/query.rb
new file mode 100644
index 0000000000000000000000000000000000000000..8f3f7b6d316aee5703ea550a6d894fea65a98a7d
--- /dev/null
+++ b/lib/gitlab/zentao/query.rb
@@ -0,0 +1,78 @@
+# frozen_string_literal: true
+
+module Gitlab
+  module Zentao
+    class Query
+      STATUSES = %w[all opened closed].freeze
+      ISSUES_DEFAULT_LIMIT = 20
+      ISSUES_MAX_LIMIT = 50
+
+      attr_reader :client, :params
+
+      def initialize(integration, params)
+        @client = Client.new(integration)
+        @params = params
+      end
+
+      def issues
+        issues_response = client.fetch_issues(query_options)
+        return [] if issues_response.blank?
+
+        Kaminari.paginate_array(
+          issues_response['issues'],
+          limit: issues_response['limit'],
+          total_count: issues_response['total']
+        )
+      end
+
+      def issue
+        issue_response = client.fetch_issue(params[:id])
+        issue_response['issue']
+      end
+
+      private
+
+      def query_options
+        {
+          order: query_order,
+          status: query_status,
+          labels: query_labels,
+          page: query_page,
+          limit: query_limit,
+          search: query_search
+        }
+      end
+
+      def query_page
+        params[:page].presence || 1
+      end
+
+      def query_limit
+        limit = params[:limit].presence || ISSUES_DEFAULT_LIMIT
+        [limit.to_i, ISSUES_MAX_LIMIT].min
+      end
+
+      def query_search
+        params[:search] || ''
+      end
+
+      def query_order
+        key, order = params['sort'].to_s.split('_', 2)
+        zentao_key = (key == 'created' ? 'openedDate' : 'lastEditedDate')
+        zentao_order = (order == 'asc' ? 'asc' : 'desc')
+
+        "#{zentao_key}_#{zentao_order}"
+      end
+
+      def query_status
+        return params[:state] if params[:state].present? && params[:state].in?(STATUSES)
+
+        'opened'
+      end
+
+      def query_labels
+        (params[:labels].presence || []).join(',')
+      end
+    end
+  end
+end
diff --git a/lib/sidebars/projects/menus/zentao_menu.rb b/lib/sidebars/projects/menus/zentao_menu.rb
new file mode 100644
index 0000000000000000000000000000000000000000..fe96fb6d9f485ceeae2e61baf1c14dac584a9c80
--- /dev/null
+++ b/lib/sidebars/projects/menus/zentao_menu.rb
@@ -0,0 +1,81 @@
+# frozen_string_literal: true
+
+module Sidebars
+  module Projects
+    module Menus
+      class ZentaoMenu < ::Sidebars::Menu
+        override :configure_menu_items
+        def configure_menu_items
+          render?.tap do |render|
+            break unless render
+
+            add_items
+          end
+        end
+
+        override :link
+        def link
+          zentao_integration.url
+        end
+
+        override :title
+        def title
+          s_('ZentaoIntegration|ZenTao issues')
+        end
+
+        override :title_html_options
+        def title_html_options
+          {
+            id: 'js-onboarding-settings-link'
+          }
+        end
+
+        override :image_path
+        def image_path
+          'logos/zentao.svg'
+        end
+
+        # Hardcode sizes so image doesn't flash before CSS loads https://gitlab.com/gitlab-org/gitlab/-/issues/321022
+        override :image_html_options
+        def image_html_options
+          {
+            size: 16
+          }
+        end
+
+        override :render?
+        def render?
+          return false if zentao_integration.blank?
+
+          zentao_integration.active?
+        end
+
+        def add_items
+          add_item(open_zentao_menu_item)
+        end
+
+        private
+
+        def zentao_integration
+          @zentao_integration ||= context.project.zentao_integration
+        end
+
+        def open_zentao_menu_item
+          ::Sidebars::MenuItem.new(
+            title: s_('ZentaoIntegration|Open ZenTao'),
+            link: zentao_integration.url,
+            active_routes: {},
+            item_id: :open_zentao,
+            sprite_icon: 'external-link',
+            container_html_options: {
+              target: '_blank',
+              rel: 'noopener noreferrer'
+            }
+          )
+        end
+      end
+    end
+  end
+end
+
+::Sidebars::Projects::Menus::ZentaoMenu.prepend_mod
diff --git a/lib/sidebars/projects/panel.rb b/lib/sidebars/projects/panel.rb
index d5311c0a0c143d20297b1c1a630a0af8d025d274..f37f404d03cd1324f2d29f8324500a0226823baf 100644
--- a/lib/sidebars/projects/panel.rb
+++ b/lib/sidebars/projects/panel.rb
@@ -23,6 +23,7 @@ def add_menus
         add_menu(Sidebars::Projects::Menus::RepositoryMenu.new(context))
         add_menu(Sidebars::Projects::Menus::IssuesMenu.new(context))
         add_menu(Sidebars::Projects::Menus::ExternalIssueTrackerMenu.new(context))
+        add_menu(Sidebars::Projects::Menus::ZentaoMenu.new(context)) if ::Integrations::Zentao.feature_flag_enabled?(context.project)
         add_menu(Sidebars::Projects::Menus::MergeRequestsMenu.new(context))
         add_menu(Sidebars::Projects::Menus::CiCdMenu.new(context))
         add_menu(Sidebars::Projects::Menus::SecurityComplianceMenu.new(context))
diff --git a/locale/gitlab.pot b/locale/gitlab.pot
index c235817cff66c61a7df50692d0e832eef5ee319e..f9fd2bd83d3c1292f2a2dfb7c537e460cec8e416 100644
--- a/locale/gitlab.pot
+++ b/locale/gitlab.pot
@@ -39678,7 +39678,13 @@ msgstr ""
 msgid "ZenTaoIntegration|ZenTao user"
 msgstr ""
 
-msgid "ZentaoIntegration|Base URL of the Zentao instance."
+msgid "Zentao issues"
+msgstr ""
+
+msgid "ZentaoIntegration|An error occurred while requesting data from the ZenTao service."
+msgstr ""
+
+msgid "ZentaoIntegration|Base URL of the ZenTao instance."
 msgstr ""
 
 msgid "ZentaoIntegration|Enter API token"
@@ -39687,19 +39693,31 @@ msgstr ""
 msgid "ZentaoIntegration|If different from Web URL."
 msgstr ""
 
-msgid "ZentaoIntegration|Use Zentao as this project's issue tracker."
+msgid "ZentaoIntegration|Issue list"
+msgstr ""
+
+msgid "ZentaoIntegration|Open ZenTao"
+msgstr ""
+
+msgid "ZentaoIntegration|Use ZenTao as this project's issue tracker."
+msgstr ""
+
+msgid "ZentaoIntegration|ZenTao API URL (optional)"
+msgstr ""
+
+msgid "ZentaoIntegration|ZenTao API token"
 msgstr ""
 
-msgid "ZentaoIntegration|Zentao API URL (optional)"
+msgid "ZentaoIntegration|ZenTao Product ID"
 msgstr ""
 
-msgid "ZentaoIntegration|Zentao API token"
+msgid "ZentaoIntegration|ZenTao Web URL"
 msgstr ""
 
-msgid "ZentaoIntegration|Zentao Product ID"
+msgid "ZentaoIntegration|ZenTao issues"
 msgstr ""
 
-msgid "ZentaoIntegration|Zentao Web URL"
+msgid "ZentaoIntegration|Zentao issues"
 msgstr ""
 
 msgid "Zoom meeting added"
diff --git a/spec/lib/gitlab/zentao/client_spec.rb b/spec/lib/gitlab/zentao/client_spec.rb
index e3a335c1e89ae890227b42fc969494f40f159d51..6e56ac3a8ff0c394d39bbce9621fbc172cbd7694 100644
--- a/spec/lib/gitlab/zentao/client_spec.rb
+++ b/spec/lib/gitlab/zentao/client_spec.rb
@@ -6,7 +6,23 @@
   subject(:integration) { described_class.new(zentao_integration) }
 
   let(:zentao_integration) { create(:zentao_integration) }
-  let(:mock_get_products_url) { integration.send(:url, "products/#{zentao_integration.zentao_product_xid}") }
+
+  def mock_get_products_url
+    integration.send(:url, "products/#{zentao_integration.zentao_product_xid}")
+  end
+
+  def mock_fetch_issue_url(issue_id)
+    integration.send(:url, "issues/#{issue_id}")
+  end
+
+  let(:mock_headers) do
+    {
+      headers: {
+        'Content-Type' => 'application/json',
+        'Token' => zentao_integration.api_token
+      }
+    }
+  end
 
   describe '#new' do
     context 'if integration is nil' do
@@ -25,15 +41,6 @@
   end
 
   describe '#fetch_product' do
-    let(:mock_headers) do
-      {
-        headers: {
-          'Content-Type' => 'application/json',
-          'Token' => zentao_integration.api_token
-        }
-      }
-    end
-
     context 'with valid product' do
       let(:mock_response) { { 'id' => zentao_integration.zentao_product_xid } }
 
@@ -54,7 +61,9 @@
       end
 
       it 'fetches the empty product' do
-        expect(integration.fetch_product(zentao_integration.zentao_product_xid)).to eq({})
+        expect do
+          integration.fetch_product(zentao_integration.zentao_product_xid)
+        end.to raise_error(Gitlab::Zentao::Client::Error)
       end
     end
 
@@ -65,21 +74,14 @@
       end
 
       it 'fetches the empty product' do
-        expect(integration.fetch_product(zentao_integration.zentao_product_xid)).to eq({})
+        expect do
+          integration.fetch_product(zentao_integration.zentao_product_xid)
+        end.to raise_error(Gitlab::Zentao::Client::Error)
       end
     end
   end
 
   describe '#ping' do
-    let(:mock_headers) do
-      {
-        headers: {
-          'Content-Type' => 'application/json',
-          'Token' => zentao_integration.api_token
-        }
-      }
-    end
-
     context 'with valid resource' do
       before do
         WebMock.stub_request(:get, mock_get_products_url)
@@ -102,4 +104,29 @@
       end
     end
   end
+
+  describe '#fetch_issue' do
+    context 'with invalid id' do
+      let(:invalid_ids) { ['story', 'story-', '-', '123', ''] }
+
+      it 'returns empty object' do
+        invalid_ids.each do |id|
+          expect { integration.fetch_issue(id) }.to raise_error(Gitlab::Zentao::Client::Error)
+        end
+      end
+    end
+
+    context 'with valid id' do
+      let(:valid_ids) { %w[story-1 bug-23] }
+
+      it 'fetches current issue' do
+        valid_ids.each do |id|
+          WebMock.stub_request(:get, mock_fetch_issue_url(id))
+                 .with(mock_headers).to_return(status: 200, body: { issue: { id: id } }.to_json)
+
+          expect(integration.fetch_issue(id).dig('issue', 'id')).to eq id
+        end
+      end
+    end
+  end
 end
diff --git a/spec/lib/gitlab/zentao/query_spec.rb b/spec/lib/gitlab/zentao/query_spec.rb
new file mode 100644
index 0000000000000000000000000000000000000000..f7495e640c32e2a9042ed12aa6881d323443c10d
--- /dev/null
+++ b/spec/lib/gitlab/zentao/query_spec.rb
@@ -0,0 +1,61 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Gitlab::Zentao::Query do
+  let(:zentao_integration) { create(:zentao_integration) }
+  let(:params) { {} }
+
+  subject(:query) { described_class.new(zentao_integration, ActionController::Parameters.new(params)) }
+
+  describe '#issues' do
+    let(:response) { { 'page' => 1, 'total' => 0, 'limit' => 20, 'issues' => [] } }
+
+    def expect_query_option_include(expected_params)
+      expect_next_instance_of(Gitlab::Zentao::Client) do |client|
+        expect(client).to receive(:fetch_issues)
+          .with(hash_including(expected_params))
+          .and_return(response)
+      end
+
+      query.issues
+    end
+
+    context 'when params are empty' do
+      it 'fills default params' do
+        expect_query_option_include(status: 'opened', order: 'lastEditedDate_desc', labels: '')
+      end
+    end
+
+    context 'when params contain valid options' do
+      let(:params) { { state: 'closed', sort: 'created_asc', labels: %w[Bugs Features] } }
+
+      it 'fills params with standard of ZenTao' do
+        expect_query_option_include(status: 'closed', order: 'openedDate_asc', labels: 'Bugs,Features')
+      end
+    end
+
+    context 'when params contain invalid options' do
+      let(:params) { { state: 'xxx', sort: 'xxx', labels: %w[xxx] } }
+
+      it 'fills default params with standard of ZenTao' do
+        expect_query_option_include(status: 'opened', order: 'lastEditedDate_desc', labels: 'xxx')
+      end
+    end
+  end
+
+  describe '#issue' do
+    let(:response) { { 'issue' => { 'id' => 'story-1' } } }
+
+    before do
+      expect_next_instance_of(Gitlab::Zentao::Client) do |client|
+        expect(client).to receive(:fetch_issue)
+          .and_return(response)
+      end
+    end
+
+    it 'returns issue object by client' do
+      expect(query.issue).to include('id' => 'story-1')
+    end
+  end
+end
diff --git a/spec/lib/sidebars/projects/menus/zentao_menu_spec.rb b/spec/lib/sidebars/projects/menus/zentao_menu_spec.rb
new file mode 100644
index 0000000000000000000000000000000000000000..f0bce6b7ea57fb310e4e94b67efde3cdb8e9d155
--- /dev/null
+++ b/spec/lib/sidebars/projects/menus/zentao_menu_spec.rb
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Sidebars::Projects::Menus::ZentaoMenu do
+  it_behaves_like 'ZenTao menu with CE version'
+end
diff --git a/spec/support/shared_examples/lib/sidebars/projects/menus/zentao_menu_shared_examples.rb b/spec/support/shared_examples/lib/sidebars/projects/menus/zentao_menu_shared_examples.rb
new file mode 100644
index 0000000000000000000000000000000000000000..d3fd28727b59170066d35c93958cd47d71d6c3ee
--- /dev/null
+++ b/spec/support/shared_examples/lib/sidebars/projects/menus/zentao_menu_shared_examples.rb
@@ -0,0 +1,42 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.shared_examples 'ZenTao menu with CE version' do
+  let(:project) { create(:project, has_external_issue_tracker: true) }
+  let(:user) { project.owner }
+  let(:context) { Sidebars::Projects::Context.new(current_user: user, container: project) }
+  let(:zentao_integration) { create(:zentao_integration, project: project) }
+
+  subject { described_class.new(context) }
+
+  describe '#render?' do
+    context 'when issues integration is disabled' do
+      before do
+        zentao_integration.update!(active: false)
+      end
+
+      it 'returns false' do
+        expect(subject.render?).to eq false
+      end
+    end
+
+    context 'when issues integration is enabled' do
+      before do
+        zentao_integration.update!(active: true)
+      end
+
+      it 'returns true' do
+        expect(subject.render?).to eq true
+      end
+
+      it 'renders menu link' do
+        expect(subject.link).to eq zentao_integration.url
+      end
+
+      it 'contains only open ZenTao item' do
+        expect(subject.renderable_items.map(&:item_id)).to match_array [:open_zentao]
+      end
+    end
+  end
+end