diff --git a/app/models/organizations/organization.rb b/app/models/organizations/organization.rb
index 0c995fc91b5335b303cf2a3400a0e3e5848f7a03..8625fde8d64fce60f33ee056577cb450197052cd 100644
--- a/app/models/organizations/organization.rb
+++ b/app/models/organizations/organization.rb
@@ -32,7 +32,8 @@ class Organization < ApplicationRecord
     has_one :organization_detail, inverse_of: :organization, autosave: true
 
     has_many :organization_users, inverse_of: :organization
-    has_many :organization_user_aliases, inverse_of: :organization
+    has_many :organization_user_aliases, inverse_of: :organization # deprecated
+    has_many :organization_user_details, inverse_of: :organization
     # if considering disable_joins on the below see:
     # https://gitlab.com/gitlab-org/gitlab/-/merge_requests/140343#note_1705047949
     has_many :users, through: :organization_users, inverse_of: :organizations
diff --git a/app/models/organizations/organization_user_detail.rb b/app/models/organizations/organization_user_detail.rb
new file mode 100644
index 0000000000000000000000000000000000000000..96862832a0327469f5e13fcd2392ed1d89650bbe
--- /dev/null
+++ b/app/models/organizations/organization_user_detail.rb
@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+module Organizations
+  class OrganizationUserDetail < ApplicationRecord
+    belongs_to :organization, inverse_of: :organization_user_details, optional: false
+    belongs_to :user, inverse_of: :organization_user_details, optional: false
+
+    validates :username, presence: true, uniqueness: { scope: :organization_id }
+    validates :display_name, presence: true
+  end
+end
diff --git a/app/models/user.rb b/app/models/user.rb
index 50e4c068db7f447784b7bb7e7fe205e767e61292..b6f16e38b4bbc312b101732d679cf51ddbadf42e 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -276,7 +276,8 @@ def update_tracked_fields!(request)
   belongs_to :created_by, class_name: 'User', optional: true
 
   has_many :organization_users, class_name: 'Organizations::OrganizationUser', inverse_of: :user
-  has_many :organization_user_aliases, class_name: 'Organizations::OrganizationUserAlias', inverse_of: :user
+  has_many :organization_user_aliases, class_name: 'Organizations::OrganizationUserAlias', inverse_of: :user # deprecated
+  has_many :organization_user_details, class_name: 'Organizations::OrganizationUserDetail', inverse_of: :user
 
   has_many :organizations, through: :organization_users, class_name: 'Organizations::Organization', inverse_of: :users,
     disable_joins: true
diff --git a/db/docs/organization_user_details.yml b/db/docs/organization_user_details.yml
new file mode 100644
index 0000000000000000000000000000000000000000..681181057aa2c5861c96f176c0b1c4c28ea9412d
--- /dev/null
+++ b/db/docs/organization_user_details.yml
@@ -0,0 +1,13 @@
+---
+table_name: organization_user_details
+classes:
+- Organizations::OrganizationUserDetail
+feature_categories:
+- cell
+description: |
+  Store organization-specific usernames and other user details. This allows users in organizations to be referenced by their organization-assigned handles (usernames) as opposed to their global, platform-wide usernames.
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/191575
+milestone: '18.1'
+gitlab_schema: gitlab_main_cell
+sharding_key:
+  organization_id: organizations
diff --git a/db/migrate/20250515190013_add_organization_user_details.rb b/db/migrate/20250515190013_add_organization_user_details.rb
new file mode 100644
index 0000000000000000000000000000000000000000..5223701ca6e384e4733a3822c135de405a64db08
--- /dev/null
+++ b/db/migrate/20250515190013_add_organization_user_details.rb
@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+class AddOrganizationUserDetails < Gitlab::Database::Migration[2.3]
+  milestone '18.1'
+
+  def change
+    create_table :organization_user_details do |t|
+      t.belongs_to :organization, null: false, index: false
+      t.belongs_to :user, null: false
+
+      t.text :username, null: false, limit: 510
+      t.text :display_name, null: false, limit: 510
+
+      t.timestamps_with_timezone null: false
+
+      t.index [:organization_id, :user_id], unique: true,
+        name: :unique_organization_user_details_organization_id_user_id
+      t.index [:organization_id, :username], unique: true,
+        name: :unique_organization_user_details_organization_id_username
+      t.index 'lower(username)'
+    end
+  end
+end
diff --git a/db/migrate/20250515190136_add_fk_organization_user_details_organizations.rb b/db/migrate/20250515190136_add_fk_organization_user_details_organizations.rb
new file mode 100644
index 0000000000000000000000000000000000000000..f1d6643aca6926f10fcae5de5c8c07e3d99a17b7
--- /dev/null
+++ b/db/migrate/20250515190136_add_fk_organization_user_details_organizations.rb
@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+
+class AddFkOrganizationUserDetailsOrganizations < Gitlab::Database::Migration[2.3]
+  disable_ddl_transaction!
+  milestone '18.1'
+
+  def up
+    add_concurrent_foreign_key :organization_user_details, :organizations, column: :organization_id, on_delete: :cascade
+  end
+
+  def down
+    with_lock_retries do
+      remove_foreign_key :organization_user_details, column: :organization_id
+    end
+  end
+end
diff --git a/db/migrate/20250515190353_add_fk_organization_user_details_users.rb b/db/migrate/20250515190353_add_fk_organization_user_details_users.rb
new file mode 100644
index 0000000000000000000000000000000000000000..53df51093df9caacdab02c6b31fd73ed6fc4478c
--- /dev/null
+++ b/db/migrate/20250515190353_add_fk_organization_user_details_users.rb
@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+
+class AddFkOrganizationUserDetailsUsers < Gitlab::Database::Migration[2.3]
+  disable_ddl_transaction!
+  milestone '18.1'
+
+  def up
+    add_concurrent_foreign_key :organization_user_details, :users, column: :user_id, on_delete: :cascade
+  end
+
+  def down
+    with_lock_retries do
+      remove_foreign_key :organization_user_details, column: :user_id
+    end
+  end
+end
diff --git a/db/schema_migrations/20250515190013 b/db/schema_migrations/20250515190013
new file mode 100644
index 0000000000000000000000000000000000000000..f459cd28cd8b18938d49764b0c2143aeb7b3826a
--- /dev/null
+++ b/db/schema_migrations/20250515190013
@@ -0,0 +1 @@
+9d67ff936bcd2fda808ec22526afe619d39d1ad41d7a6421a0050e78f5c74457
\ No newline at end of file
diff --git a/db/schema_migrations/20250515190136 b/db/schema_migrations/20250515190136
new file mode 100644
index 0000000000000000000000000000000000000000..759ae997dd274838e8dfce44869e4b1572faecce
--- /dev/null
+++ b/db/schema_migrations/20250515190136
@@ -0,0 +1 @@
+1da7143e770d4b4445f30b661b10aa8d3fb843eaa4766976985041fcdf71700a
\ No newline at end of file
diff --git a/db/schema_migrations/20250515190353 b/db/schema_migrations/20250515190353
new file mode 100644
index 0000000000000000000000000000000000000000..f6d023ad51a0e78a5b9356f7c204de3f2d6871e1
--- /dev/null
+++ b/db/schema_migrations/20250515190353
@@ -0,0 +1 @@
+f81dbd3fb12060afecb19f95ea8cd76f6ec53497e897ad7a39bf3d162aa36f7b
\ No newline at end of file
diff --git a/db/structure.sql b/db/structure.sql
index cdbc01dc31926bbb1e4636b3b810b7d8a2c80599..16309b5d899ce37285377b07fb3e3b88211363e9 100644
--- a/db/structure.sql
+++ b/db/structure.sql
@@ -18814,6 +18814,27 @@ CREATE SEQUENCE organization_user_aliases_id_seq
 
 ALTER SEQUENCE organization_user_aliases_id_seq OWNED BY organization_user_aliases.id;
 
+CREATE TABLE organization_user_details (
+    id bigint NOT NULL,
+    organization_id bigint NOT NULL,
+    user_id bigint NOT NULL,
+    username text NOT NULL,
+    display_name text NOT NULL,
+    created_at timestamp with time zone NOT NULL,
+    updated_at timestamp with time zone NOT NULL,
+    CONSTRAINT check_470dbccf9b CHECK ((char_length(display_name) <= 510)),
+    CONSTRAINT check_dc5e9cf6f2 CHECK ((char_length(username) <= 510))
+);
+
+CREATE SEQUENCE organization_user_details_id_seq
+    START WITH 1
+    INCREMENT BY 1
+    NO MINVALUE
+    NO MAXVALUE
+    CACHE 1;
+
+ALTER SEQUENCE organization_user_details_id_seq OWNED BY organization_user_details.id;
+
 CREATE TABLE organization_users (
     id bigint NOT NULL,
     organization_id bigint NOT NULL,
@@ -27743,6 +27764,8 @@ ALTER TABLE ONLY organization_push_rules ALTER COLUMN id SET DEFAULT nextval('or
 
 ALTER TABLE ONLY organization_user_aliases ALTER COLUMN id SET DEFAULT nextval('organization_user_aliases_id_seq'::regclass);
 
+ALTER TABLE ONLY organization_user_details ALTER COLUMN id SET DEFAULT nextval('organization_user_details_id_seq'::regclass);
+
 ALTER TABLE ONLY organization_users ALTER COLUMN id SET DEFAULT nextval('organization_users_id_seq'::regclass);
 
 ALTER TABLE ONLY organizations ALTER COLUMN id SET DEFAULT nextval('organizations_id_seq'::regclass);
@@ -30466,6 +30489,9 @@ ALTER TABLE ONLY organization_settings
 ALTER TABLE ONLY organization_user_aliases
     ADD CONSTRAINT organization_user_aliases_pkey PRIMARY KEY (id);
 
+ALTER TABLE ONLY organization_user_details
+    ADD CONSTRAINT organization_user_details_pkey PRIMARY KEY (id);
+
 ALTER TABLE ONLY organization_users
     ADD CONSTRAINT organization_users_pkey PRIMARY KEY (id);
 
@@ -36510,6 +36536,10 @@ CREATE UNIQUE INDEX index_organization_push_rules_on_organization_id ON organiza
 
 CREATE INDEX index_organization_user_aliases_on_user_id ON organization_user_aliases USING btree (user_id);
 
+CREATE INDEX index_organization_user_details_on_lower_username ON organization_user_details USING btree (lower(username));
+
+CREATE INDEX index_organization_user_details_on_user_id ON organization_user_details USING btree (user_id);
+
 CREATE INDEX index_organization_users_on_org_id_access_level_user_id ON organization_users USING btree (organization_id, access_level, user_id);
 
 CREATE INDEX index_organization_users_on_organization_id_and_id ON organization_users USING btree (organization_id, id);
@@ -38914,6 +38944,10 @@ CREATE UNIQUE INDEX unique_organization_user_alias_organization_id_user_id ON or
 
 CREATE UNIQUE INDEX unique_organization_user_alias_organization_id_username ON organization_user_aliases USING btree (organization_id, username);
 
+CREATE UNIQUE INDEX unique_organization_user_details_organization_id_user_id ON organization_user_details USING btree (organization_id, user_id);
+
+CREATE UNIQUE INDEX unique_organization_user_details_organization_id_username ON organization_user_details USING btree (organization_id, username);
+
 CREATE UNIQUE INDEX unique_organizations_on_path_case_insensitive ON organizations USING btree (lower(path));
 
 CREATE UNIQUE INDEX unique_packages_project_id_and_name_and_version_when_debian ON packages_packages USING btree (project_id, name, version) WHERE ((package_type = 9) AND (status <> 4));
@@ -42611,6 +42645,9 @@ ALTER TABLE ONLY todos
 ALTER TABLE ONLY merge_requests_approval_rules_projects
     ADD CONSTRAINT fk_451a9dfe93 FOREIGN KEY (approval_rule_id) REFERENCES merge_requests_approval_rules(id) ON DELETE CASCADE;
 
+ALTER TABLE ONLY organization_user_details
+    ADD CONSTRAINT fk_4533918f8e FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE;
+
 ALTER TABLE ONLY ai_settings
     ADD CONSTRAINT fk_4571bb0ccc FOREIGN KEY (duo_workflow_oauth_application_id) REFERENCES oauth_applications(id) ON DELETE SET NULL;
 
@@ -42860,6 +42897,9 @@ ALTER TABLE ONLY ci_pipeline_chat_data
 ALTER TABLE ONLY cluster_agent_tokens
     ADD CONSTRAINT fk_64f741f626 FOREIGN KEY (project_id) REFERENCES projects(id) ON DELETE CASCADE;
 
+ALTER TABLE ONLY organization_user_details
+    ADD CONSTRAINT fk_657140ae14 FOREIGN KEY (organization_id) REFERENCES organizations(id) ON DELETE CASCADE;
+
 ALTER TABLE ONLY container_repository_states
     ADD CONSTRAINT fk_6591698505 FOREIGN KEY (project_id) REFERENCES projects(id) ON DELETE CASCADE;
 
diff --git a/spec/factories/organizations/organization_user_details.rb b/spec/factories/organizations/organization_user_details.rb
new file mode 100644
index 0000000000000000000000000000000000000000..1e2377684ebe66ad863d9b7f4572cebc29e1f689
--- /dev/null
+++ b/spec/factories/organizations/organization_user_details.rb
@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+FactoryBot.define do
+  factory :organization_user_detail, class: 'Organizations::OrganizationUserDetail' do
+    user
+    organization
+
+    sequence(:username) { |n| "user_alias_#{n}" }
+    display_name { username.humanize.titleize }
+  end
+end
diff --git a/spec/models/organizations/organization_user_detail_spec.rb b/spec/models/organizations/organization_user_detail_spec.rb
new file mode 100644
index 0000000000000000000000000000000000000000..268f6009db94ec29f1c94c9d5df685e0de0b4c51
--- /dev/null
+++ b/spec/models/organizations/organization_user_detail_spec.rb
@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Organizations::OrganizationUserDetail, type: :model, feature_category: :cell do
+  describe 'associations' do
+    it { is_expected.to belong_to(:organization).inverse_of(:organization_user_details).required }
+    it { is_expected.to belong_to(:user).inverse_of(:organization_user_details).required }
+  end
+
+  describe 'validations' do
+    subject { build(:organization_user_detail) }
+
+    it { is_expected.to validate_presence_of(:username) }
+    it { is_expected.to validate_presence_of(:display_name) }
+    it { is_expected.to validate_uniqueness_of(:username).scoped_to(:organization_id) }
+  end
+end