diff --git a/src/authentication/noop.py b/src/authentication/noop.py
index 8d0e9bd84..259dd1168 100644
--- a/src/authentication/noop.py
+++ b/src/authentication/noop.py
@@ -1,6 +1,6 @@
 """Manage authentication flow for FastAPI endpoints with no-op auth."""
 
-from fastapi import Request
+from fastapi import HTTPException, Request
 
 from constants import (
     DEFAULT_USER_NAME,
@@ -50,5 +50,7 @@ async def __call__(self, request: Request) -> tuple[str, str, bool, str]:
         )
         # try to extract user ID from request
         user_id = request.query_params.get("user_id", DEFAULT_USER_UID)
+        if not user_id:
+            raise HTTPException(status_code=400, detail="user_id cannot be empty")
         logger.debug("Retrieved user ID: %s", user_id)
         return user_id, DEFAULT_USER_NAME, self.skip_userid_check, NO_USER_TOKEN
diff --git a/src/authentication/noop_with_token.py b/src/authentication/noop_with_token.py
index 3d1b0ed98..6d7777044 100644
--- a/src/authentication/noop_with_token.py
+++ b/src/authentication/noop_with_token.py
@@ -9,7 +9,7 @@
 - Returns a tuple: (user_id, DEFAULT_USER_NAME, user_token).
 """
 
-from fastapi import Request
+from fastapi import HTTPException, Request
 
 from constants import (
     DEFAULT_USER_NAME,
@@ -63,5 +63,7 @@ async def __call__(self, request: Request) -> tuple[str, str, bool, str]:
         user_token = extract_user_token(request.headers)
         # try to extract user ID from request
         user_id = request.query_params.get("user_id", DEFAULT_USER_UID)
+        if not user_id:
+            raise HTTPException(status_code=400, detail="user_id cannot be empty")
         logger.debug("Retrieved user ID: %s", user_id)
         return user_id, DEFAULT_USER_NAME, self.skip_userid_check, user_token
diff --git a/tests/e2e/features/authorized_noop.feature b/tests/e2e/features/authorized_noop.feature
index 62edb9bf9..7da0ef959 100644
--- a/tests/e2e/features/authorized_noop.feature
+++ b/tests/e2e/features/authorized_noop.feature
@@ -35,14 +35,14 @@ Feature: Authorized endpoint API tests for the noop authentication module
             {"user_id": "00000000-0000-0000-0000-000","username": "lightspeed-user","skip_userid_check": true}
           """
 
-  Scenario: Check if the authorized endpoint works when providing empty user_id
+  Scenario: Check if the authorized endpoint rejects empty user_id
     Given The system is in default state
     And I set the Authorization header to Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6Ikpva
      When I access endpoint "authorized" using HTTP POST method with user_id ""
-     Then The status code of the response is 200
+     Then The status code of the response is 400
       And The body of the response is the following
           """
-            {"user_id": "","username": "lightspeed-user","skip_userid_check": true}
+            {"detail": "user_id cannot be empty"}
           """
 
   Scenario: Check if the authorized endpoint works when providing proper user_id
diff --git a/tests/e2e/features/authorized_noop_token.feature b/tests/e2e/features/authorized_noop_token.feature
index b654a77d2..f977790f5 100644
--- a/tests/e2e/features/authorized_noop_token.feature
+++ b/tests/e2e/features/authorized_noop_token.feature
@@ -32,14 +32,14 @@ Feature: Authorized endpoint API tests for the noop-with-token authentication mo
             {"user_id": "00000000-0000-0000-0000-000","username": "lightspeed-user","skip_userid_check": true}
           """
 
-  Scenario: Check if the authorized endpoint works when providing empty user_id
+  Scenario: Check if the authorized endpoint rejects empty user_id
     Given The system is in default state
     And I set the Authorization header to Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6Ikpva
      When I access endpoint "authorized" using HTTP POST method with user_id ""
-     Then The status code of the response is 200
+     Then The status code of the response is 400
       And The body of the response is the following
           """
-            {"user_id": "","username": "lightspeed-user","skip_userid_check": true}
+            {"detail": "user_id cannot be empty"}
           """
 
   Scenario: Check if the authorized endpoint works when providing proper user_id
diff --git a/tests/unit/authentication/test_noop.py b/tests/unit/authentication/test_noop.py
index e651ff673..d179f33e7 100644
--- a/tests/unit/authentication/test_noop.py
+++ b/tests/unit/authentication/test_noop.py
@@ -1,6 +1,8 @@
 """Unit tests for functions defined in authentication/noop.py"""
 
-from fastapi import Request
+from fastapi import Request, HTTPException
+import pytest
+
 from authentication.noop import NoopAuthDependency
 from constants import DEFAULT_USER_NAME, DEFAULT_USER_UID, NO_USER_TOKEN
 
@@ -37,3 +39,18 @@ async def test_noop_auth_dependency_custom_user_id() -> None:
     assert username == DEFAULT_USER_NAME
     assert skip_userid_check is True
     assert user_token == NO_USER_TOKEN
+
+
+async def test_noop_auth_dependency_empty_user_id() -> None:
+    """Test that NoopAuthDependency rejects empty user_id with HTTP 400."""
+    dependency = NoopAuthDependency()
+
+    # Create a mock request with empty user_id
+    request = Request(scope={"type": "http", "query_string": b"user_id="})
+
+    # Assert that an HTTPException is raised for empty user_id
+    with pytest.raises(HTTPException) as exc_info:
+        await dependency(request)
+
+    assert exc_info.value.status_code == 400
+    assert exc_info.value.detail == "user_id cannot be empty"
diff --git a/tests/unit/authentication/test_noop_with_token.py b/tests/unit/authentication/test_noop_with_token.py
index 9d08a87a3..d120f072b 100644
--- a/tests/unit/authentication/test_noop_with_token.py
+++ b/tests/unit/authentication/test_noop_with_token.py
@@ -117,3 +117,26 @@ async def test_noop_with_token_auth_dependency_no_bearer() -> None:
     detail = cast(dict[str, str], exc_info.value.detail)
     assert detail["response"] == ("Missing or invalid credentials provided by client")
     assert detail["cause"] == "No token found in Authorization header"
+
+
+async def test_noop_with_token_auth_dependency_empty_user_id() -> None:
+    """Test that NoopWithTokenAuthDependency rejects empty user_id with HTTP 400."""
+    dependency = NoopWithTokenAuthDependency()
+
+    # Create a mock request with empty user_id but valid token
+    request = Request(
+        scope={
+            "type": "http",
+            "query_string": b"user_id=",
+            "headers": [
+                (b"authorization", b"Bearer spongebob-token"),
+            ],
+        },
+    )
+
+    # Assert that an HTTPException is raised for empty user_id
+    with pytest.raises(HTTPException) as exc_info:
+        await dependency(request)
+
+    assert exc_info.value.status_code == 400
+    assert exc_info.value.detail == "user_id cannot be empty"