diff --git a/api/controllers/console/setup.py b/api/controllers/console/setup.py
index 7fa02ae280..ed22ef045d 100644
--- a/api/controllers/console/setup.py
+++ b/api/controllers/console/setup.py
@@ -84,10 +84,11 @@ class SetupApi(Resource):
             raise NotInitValidateError()
 
         args = SetupRequestPayload.model_validate(console_ns.payload)
+        normalized_email = args.email.lower()
 
         # setup
         RegisterService.setup(
-            email=args.email,
+            email=normalized_email,
             name=args.name,
             password=args.password,
             ip_address=extract_remote_ip(request),
diff --git a/api/tests/unit_tests/controllers/console/test_setup.py b/api/tests/unit_tests/controllers/console/test_setup.py
new file mode 100644
index 0000000000..900bdbc8a9
--- /dev/null
+++ b/api/tests/unit_tests/controllers/console/test_setup.py
@@ -0,0 +1,43 @@
+from types import SimpleNamespace
+from unittest.mock import patch
+
+from controllers.console.setup import SetupApi
+
+
+class TestSetupApi:
+    def test_post_lowercases_email_before_register(self):
+        """Ensure setup registration normalizes email casing."""
+        payload = {
+            "email": "Admin@Example.com",
+            "name": "Admin User",
+            "password": "ValidPass123!",
+            "language": "en-US",
+        }
+        setup_api = SetupApi(api=None)
+
+        mock_console_ns = SimpleNamespace(payload=payload)
+
+        with patch("controllers.console.setup.console_ns", mock_console_ns), patch(
+            "controllers.console.setup.get_setup_status", return_value=False
+        ), patch(
+            "controllers.console.setup.TenantService.get_tenant_count", return_value=0
+        ), patch(
+            "controllers.console.setup.get_init_validate_status", return_value=True
+        ), patch(
+            "controllers.console.setup.extract_remote_ip", return_value="127.0.0.1"
+        ), patch(
+            "controllers.console.setup.request", object()
+        ), patch(
+            "controllers.console.setup.RegisterService.setup"
+        ) as mock_register:
+            response, status = setup_api.post()
+
+        assert response == {"result": "success"}
+        assert status == 201
+        mock_register.assert_called_once_with(
+            email="admin@example.com",
+            name=payload["name"],
+            password=payload["password"],
+            ip_address="127.0.0.1",
+            language=payload["language"],
+        )