diff --git a/ansible_base/authentication/utils/authentication.py b/ansible_base/authentication/utils/authentication.py
index 8d87ad967..b7dadaba8 100644
--- a/ansible_base/authentication/utils/authentication.py
+++ b/ansible_base/authentication/utils/authentication.py
@@ -137,7 +137,10 @@ def determine_username_from_uid_social(**kwargs) -> dict:
     if authenticator.setting('USERNAME_IS_FULL_EMAIL', False):
         selected_username = kwargs.get('details', {}).get('email', None)
     else:
-        selected_username = kwargs.get('details', {}).get('username', None)
+        if authenticator.type == 'SAML':
+            selected_username = kwargs.get('uid', None)
+        else:
+            selected_username = kwargs.get('details', {}).get('username', None)
     if not selected_username:
         raise_auth_exception(
             _('Unable to get associated username from details, expected entry "username". Full user details: %(details)s')
diff --git a/test_app/tests/authentication/utils/test_authentication.py b/test_app/tests/authentication/utils/test_authentication.py
index 4a0f0b017..0ed035fec 100644
--- a/test_app/tests/authentication/utils/test_authentication.py
+++ b/test_app/tests/authentication/utils/test_authentication.py
@@ -249,6 +249,27 @@ def test_determine_username_from_uid_social_happy_path(self, ldap_authenticator)
         )
         assert response == {'username': 'Bob'}
 
+    @pytest.mark.parametrize(
+        "auth_fixture, expected_username, uid_param, details_username",
+        [
+            # SAML authenticator uses uid parameter (line 141)
+            ("saml_authenticator", "SamlUser", "SamlUser", "should_not_be_used"),
+            # Non-SAML authenticators use details['username'] (line 143)
+            ("ldap_authenticator", "LdapUser", "should_not_be_used", "LdapUser"),
+            ("oidc_authenticator", "OidcUser", "should_not_be_used", "OidcUser"),
+            ("keycloak_authenticator", "KeycloakUser", "should_not_be_used", "KeycloakUser"),
+        ],
+    )
+    def test_determine_username_from_uid_social_authenticator_types(self, request, auth_fixture, expected_username, uid_param, details_username):
+        """Test username selection logic for different authenticator types (lines 140-143)"""
+        authenticator = request.getfixturevalue(auth_fixture)
+        response = authentication.determine_username_from_uid_social(
+            details={'username': details_username},
+            backend=get_authenticator_class(authenticator.type)(database_instance=authenticator),
+            uid=uid_param,
+        )
+        assert response == {'username': expected_username}
+
     def test_raise_auth_exception(self):
         try:
             authentication.raise_auth_exception('testing')