diff --git a/custom/conf/app.example.ini b/custom/conf/app.example.ini
index 64667e4..2b0e090 100644
--- a/custom/conf/app.example.ini
+++ b/custom/conf/app.example.ini
@@ -1735,8 +1735,9 @@ LEVEL = Info
 ;; userid = use the userid / sub attribute
 ;; nickname = use the nickname attribute
 ;; preferred_username = use the preferred_username attribute
+;; employee_id = use the employee_id attribute (requires the provider to return this custom claim)
 ;; email = use the username part of the email attribute
-;; Note: `nickname`, `preferred_username` and `email` options will normalize input strings using the following criteria:
+;; Note: `nickname`, `preferred_username`, `employee_id` and `email` options will normalize input strings using the following criteria:
 ;; - diacritics are removed
 ;; - the characters in the set ['´`] are removed
 ;; - the characters in the set [\s~+] are replaced with "-"
diff --git a/modules/setting/oauth2.go b/modules/setting/oauth2.go
index f43a374..e143cb6 100644
--- a/modules/setting/oauth2.go
+++ b/modules/setting/oauth2.go
@@ -20,11 +20,12 @@ const (
 	OAuth2UsernameNickname          OAuth2UsernameType = "nickname"           // use nickname field
 	OAuth2UsernameEmail             OAuth2UsernameType = "email"              // use email field
 	OAuth2UsernamePreferredUsername OAuth2UsernameType = "preferred_username" // use preferred_username field
+	OAuth2UsernameEmployeeID        OAuth2UsernameType = "employee_id"        // use employee_id field
 )
 
 func (username OAuth2UsernameType) isValid() bool {
 	switch username {
-	case OAuth2UsernameUserid, OAuth2UsernameNickname, OAuth2UsernameEmail, OAuth2UsernamePreferredUsername:
+	case OAuth2UsernameUserid, OAuth2UsernameNickname, OAuth2UsernameEmail, OAuth2UsernamePreferredUsername, OAuth2UsernameEmployeeID:
 		return true
 	}
 	return false
diff --git a/modules/setting/oauth2_test.go b/modules/setting/oauth2_test.go
index fccff21..3ad0f49 100644
--- a/modules/setting/oauth2_test.go
+++ b/modules/setting/oauth2_test.go
@@ -88,3 +88,11 @@ ENABLE_OPENID_CONNECT_PKCE = true
 	loadOAuth2ClientFrom(cfg)
 	assert.True(t, OAuth2Client.EnableOpenIDConnectPKCE)
 }
+
+func TestOAuth2ClientEmployeeIDUsername(t *testing.T) {
+	cfg, _ := NewConfigProviderFromData(`[oauth2_client]
+USERNAME = employee_id
+`)
+	loadOAuth2ClientFrom(cfg)
+	assert.Equal(t, OAuth2UsernameEmployeeID, OAuth2Client.Username)
+}
diff --git a/routers/web/auth/auth.go b/routers/web/auth/auth.go
index f808734..edde656 100644
--- a/routers/web/auth/auth.go
+++ b/routers/web/auth/auth.go
@@ -450,6 +450,11 @@ func extractUserNameFromOAuth2(gothUser *goth.User) (string, error) {
 			return user_model.NormalizeUserName(preferredUsername)
 		}
 		return "", nil
+	case setting.OAuth2UsernameEmployeeID:
+		if employeeID, ok := gothUser.RawData["employee_id"].(string); ok {
+			return user_model.NormalizeUserName(employeeID)
+		}
+		return "", nil
 	case setting.OAuth2UsernameNickname:
 		return user_model.NormalizeUserName(gothUser.NickName)
 	default: // OAuth2UsernameUserid
diff --git a/routers/web/auth/auth_test.go b/routers/web/auth/auth_test.go
index 5d2b909..73880bd 100644
--- a/routers/web/auth/auth_test.go
+++ b/routers/web/auth/auth_test.go
@@ -184,6 +184,20 @@ func TestWebAuthOAuth2(t *testing.T) {
 	})
 }
 
+func TestExtractUserNameFromOAuth2EmployeeID(t *testing.T) {
+	defer test.MockVariableValue(&setting.OAuth2Client.Username, setting.OAuth2UsernameEmployeeID)()
+
+	username, err := extractUserNameFromOAuth2(&goth.User{
+		RawData: map[string]any{"employee_id": "RC001"},
+	})
+	require.NoError(t, err)
+	assert.Equal(t, "RC001", username)
+
+	username, err = extractUserNameFromOAuth2(&goth.User{RawData: map[string]any{}})
+	require.NoError(t, err)
+	assert.Empty(t, username)
+}
+
 func TestOpenIDRequireTwoFactor(t *testing.T) {
 	require.NoError(t, unittest.PrepareTestDatabase())
 	mockOpt := contexttest.MockContextOption{SessionStore: session.NewMockMemStore("dummy-sid-openid")}
diff --git a/routers/web/auth/oauth.go b/routers/web/auth/oauth.go
index 72b9c4f..ca6136b 100644
--- a/routers/web/auth/oauth.go
+++ b/routers/web/auth/oauth.go
@@ -160,6 +160,8 @@ func SignInOAuthCallback(ctx *context.Context) {
 					missingFields = append(missingFields, "nickname")
 				case setting.OAuth2UsernamePreferredUsername:
 					missingFields = append(missingFields, "preferred_username")
+				case setting.OAuth2UsernameEmployeeID:
+					missingFields = append(missingFields, "employee_id")
 				} // else: "UserID" and "Email" have been handled above separately
 			}
 			if len(missingFields) > 0 {