diff --git a/app/models/integration.rb b/app/models/integration.rb
index 29d96650a813becdc7c9706e34f42348c5fa3f8a..8007c41683f2aecf6ec3c5219cbd04889dfcac12 100644
--- a/app/models/integration.rb
+++ b/app/models/integration.rb
@@ -74,6 +74,10 @@ class Integration < ApplicationRecord
   validate :validate_belongs_to_project_or_group
 
   scope :external_issue_trackers, -> { where(category: 'issue_tracker').active }
+  scope :third_party_wikis, -> { where(type: %w[ConfluenceService ShimoService]).active }
+  # TODO: Will be modified in 14.7
+  # Details: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/74501#note_744393645
+  # scope :third_party_wikis, -> { where(category: 'third_party_wiki').active }
   scope :external_wikis, -> { where(type: 'ExternalWikiService').active }
   scope :active, -> { where(active: true) }
   scope :by_type, -> (type) { where(type: type) }
diff --git a/app/models/integrations/base_third_party_wiki.rb b/app/models/integrations/base_third_party_wiki.rb
new file mode 100644
index 0000000000000000000000000000000000000000..67d516c6b58005f00670f96d57cddd1e8cd6f5ae
--- /dev/null
+++ b/app/models/integrations/base_third_party_wiki.rb
@@ -0,0 +1,36 @@
+# frozen_string_literal: true
+
+module Integrations
+  class BaseThirdPartyWiki < Integration
+    default_value_for :category, 'third_party_wiki'
+
+    validate :only_one_third_party_wiki, if: :activated?, on: :manual_change
+
+    after_commit :cache_project_has_integration
+
+    def self.supported_events
+      %w()
+    end
+
+    private
+
+    def only_one_third_party_wiki
+      return unless project_level?
+
+      if project.integrations.third_party_wikis.where.not(id: id).any?
+        errors.add(:base, _('Another third-party wiki is already in use. Only one third-party wiki service can be active at a time'))
+      end
+    end
+
+    def cache_project_has_integration
+      return unless project && !project.destroyed?
+
+      project.project_setting.save! unless project.project_setting.persisted?
+      project.project_setting.update_column(project_settings_cache_key, active?)
+    end
+
+    def project_settings_cache_key
+      "has_#{self.class.name.demodulize.underscore}"
+    end
+  end
+end
diff --git a/app/models/integrations/confluence.rb b/app/models/integrations/confluence.rb
index 7f111f482dddba46170ce9a3cfff2d9e6008b227..d843878565ea0607f2a2f85a81ee4553e6b33648 100644
--- a/app/models/integrations/confluence.rb
+++ b/app/models/integrations/confluence.rb
@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 module Integrations
-  class Confluence < Integration
+  class Confluence < BaseThirdPartyWiki
     include ActionView::Helpers::UrlHelper
 
     VALID_SCHEME_MATCH = %r{\Ahttps?\Z}.freeze
@@ -13,16 +13,10 @@ class Confluence < Integration
     validates :confluence_url, presence: true, if: :activated?
     validate :validate_confluence_url_is_cloud, if: :activated?
 
-    after_commit :cache_project_has_confluence
-
     def self.to_param
       'confluence'
     end
 
-    def self.supported_events
-      %w()
-    end
-
     def title
       s_('ConfluenceService|Confluence Workspace')
     end
@@ -82,12 +76,5 @@ def confluence_uri_valid?
     rescue URI::InvalidURIError
       false
     end
-
-    def cache_project_has_confluence
-      return unless project && !project.destroyed?
-
-      project.project_setting.save! unless project.project_setting.persisted?
-      project.project_setting.update_column(:has_confluence, active?)
-    end
   end
 end
diff --git a/app/models/integrations/shimo.rb b/app/models/integrations/shimo.rb
index 0e1023bb7a7b8030082e381369ee60734ee90843..dd25a0bc558ac5ce83f17a678c679ab06104c9f3 100644
--- a/app/models/integrations/shimo.rb
+++ b/app/models/integrations/shimo.rb
@@ -1,12 +1,10 @@
 # frozen_string_literal: true
 
 module Integrations
-  class Shimo < Integration
+  class Shimo < BaseThirdPartyWiki
     prop_accessor :external_wiki_url
     validates :external_wiki_url, presence: true, public_url: true, if: :activated?
 
-    after_commit :cache_project_has_shimo
-
     def render?
       return false unless Feature.enabled?(:shimo_integration, project)
 
@@ -33,10 +31,6 @@ def execute(_data)
       nil
     end
 
-    def self.supported_events
-      %w()
-    end
-
     def fields
       [
         {
@@ -47,14 +41,5 @@ def fields
         }
       ]
     end
-
-    private
-
-    def cache_project_has_shimo
-      return unless project && !project.destroyed?
-
-      project.project_setting.save! unless project.project_setting.persisted?
-      project.project_setting.update_column(:has_shimo, activated?)
-    end
   end
 end
diff --git a/db/post_migrate/20211129073034_update_shimo_service_category.rb b/db/post_migrate/20211129073034_update_shimo_service_category.rb
new file mode 100644
index 0000000000000000000000000000000000000000..cc241c5b841f6d66aab701eaffdff69718a70d4e
--- /dev/null
+++ b/db/post_migrate/20211129073034_update_shimo_service_category.rb
@@ -0,0 +1,12 @@
+# frozen_string_literal: true
+
+class UpdateShimoServiceCategory < Gitlab::Database::Migration[1.0]
+  disable_ddl_transaction!
+  def up
+    Integrations::Shimo.update_all(category: 'third_party_wiki')
+  end
+
+  def down
+    Integrations::Shimo.update_all(category: 'common')
+  end
+end
diff --git a/db/post_migrate/20211129073035_update_confluence_service_category.rb b/db/post_migrate/20211129073035_update_confluence_service_category.rb
new file mode 100644
index 0000000000000000000000000000000000000000..3d8420732bd0182de3e9dab035408cc725ab9dcf
--- /dev/null
+++ b/db/post_migrate/20211129073035_update_confluence_service_category.rb
@@ -0,0 +1,12 @@
+# frozen_string_literal: true
+
+class UpdateConfluenceServiceCategory < Gitlab::Database::Migration[1.0]
+  disable_ddl_transaction!
+  def up
+    Integrations::Confluence.update_all(category: 'third_party_wiki')
+  end
+
+  def down
+    Integrations::Confluence.update_all(category: 'common')
+  end
+end
diff --git a/db/schema_migrations/20211129073034 b/db/schema_migrations/20211129073034
new file mode 100644
index 0000000000000000000000000000000000000000..38f9e68191ca1802fba3c670d989ead887ebb1c7
--- /dev/null
+++ b/db/schema_migrations/20211129073034
@@ -0,0 +1 @@
+8d1cdf689dc422a435978d359680c2d2a684f73ad588c5c4388f01782fba17d1
\ No newline at end of file
diff --git a/db/schema_migrations/20211129073035 b/db/schema_migrations/20211129073035
new file mode 100644
index 0000000000000000000000000000000000000000..1535a69f0dd7c4d1ba43978cf932bc0e8c81d699
--- /dev/null
+++ b/db/schema_migrations/20211129073035
@@ -0,0 +1 @@
+4863f144eedf72c9b42e49f3b9a3dd07f01e783afade9538187658a7f632d58f
\ No newline at end of file
diff --git a/lib/sidebars/projects/panel.rb b/lib/sidebars/projects/panel.rb
index 6bb4fb52e2ad6955278adf255aae0c065c33fbed..ee982d4eff26ddb982e48aa81888955350755857 100644
--- a/lib/sidebars/projects/panel.rb
+++ b/lib/sidebars/projects/panel.rb
@@ -46,15 +46,17 @@ def add_invite_members_menu
       end
 
       def add_wiki_menus
-        add_menu((third_party_wiki_menu || Sidebars::Projects::Menus::WikiMenu).new(context))
+        third_party_wiki_menus.each { |menu| add_menu(menu.new(context)) }
         add_menu(Sidebars::Projects::Menus::ExternalWikiMenu.new(context))
       end
 
-      def third_party_wiki_menu
+      def third_party_wiki_menus
         wiki_menu_list = [::Sidebars::Projects::Menus::ConfluenceMenu]
         wiki_menu_list << ::Sidebars::Projects::Menus::ShimoMenu if Feature.enabled?(:shimo_integration, context.project)
 
-        wiki_menu_list.find { |wiki_menu| wiki_menu.new(context).render? }
+        wiki_menu_list.filter do |wiki_menu|
+          wiki_menu.new(context).render?
+        end.presence || [Sidebars::Projects::Menus::WikiMenu]
       end
     end
   end
diff --git a/locale/gitlab.pot b/locale/gitlab.pot
index 74049e27dacb17ce307bc3b2c3b7f1c5c567e6ee..7326acd9c91b246ee04072d567a2c0c601399b1c 100644
--- a/locale/gitlab.pot
+++ b/locale/gitlab.pot
@@ -4003,6 +4003,9 @@ msgstr ""
 msgid "Another issue tracker is already in use. Only one issue tracker service can be active at a time"
 msgstr ""
 
+msgid "Another third-party wiki is already in use. Only one third-party wiki service can be active at a time"
+msgstr ""
+
 msgid "Anti-spam verification"
 msgstr ""
 
diff --git a/spec/models/integrations/base_third_party_wiki_spec.rb b/spec/models/integrations/base_third_party_wiki_spec.rb
new file mode 100644
index 0000000000000000000000000000000000000000..1511185df50a025456430df7c9e736cc3397cd3a
--- /dev/null
+++ b/spec/models/integrations/base_third_party_wiki_spec.rb
@@ -0,0 +1,34 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Integrations::BaseThirdPartyWiki do
+  describe 'Validations' do
+    let_it_be_with_reload(:project) { create(:project) }
+
+    describe 'only one third party wiki per project' do
+      subject(:integration) { create(:shimo_integration, project: project, active: true) }
+
+      before do
+        create(:confluence_integration, project: project, active: true)
+      end
+
+      context 'when integration is changed manually by user' do
+        it 'executes the validation' do
+          valid = integration.valid?(:manual_change)
+
+          expect(valid).to be_falsey
+          expect(integration.errors[:base]).to include(
+            _('Another third-party wiki is already in use. Only one third-party wiki service can be active at a time')
+          )
+        end
+      end
+
+      context 'when integration is changed internally' do
+        it 'does not execute the validation' do
+          expect(integration.valid?).to be_truthy
+        end
+      end
+    end
+  end
+end