diff --git a/oauth2_provider/views/introspect.py b/oauth2_provider/views/introspect.py
index 5474c3a7e..d3fb18b51 100644
--- a/oauth2_provider/views/introspect.py
+++ b/oauth2_provider/views/introspect.py
@@ -35,6 +35,11 @@ def get_token_response(token_value=None):
             )
         except ObjectDoesNotExist:
             return JsonResponse({"active": False}, status=200)
+        except AttributeError:
+            return JsonResponse(
+                {"error": "invalid_request", "error_description": "Token parameter is missing."},
+                status=400,
+            )
         else:
             if token.is_valid():
                 data = {
diff --git a/tests/test_introspection_view.py b/tests/test_introspection_view.py
index 3db23bbcd..ad7d8983d 100644
--- a/tests/test_introspection_view.py
+++ b/tests/test_introspection_view.py
@@ -279,6 +279,20 @@ def test_view_post_notexisting_token(self):
             },
         )
 
+    def test_view_post_no_token(self):
+        """
+        Test that when you pass no token HTTP 400 is returned
+        """
+        auth_headers = {
+            "HTTP_AUTHORIZATION": "Bearer " + self.resource_server_token.token,
+        }
+        response = self.client.post(reverse("oauth2_provider:introspect"), **auth_headers)
+
+        self.assertEqual(response.status_code, 400)
+        content = response.json()
+        self.assertIsInstance(content, dict)
+        self.assertEqual(content["error"], "invalid_request")
+
     def test_view_post_valid_client_creds_basic_auth(self):
         """Test HTTP basic auth working"""
         auth_headers = get_basic_auth_header(self.application.client_id, CLEARTEXT_SECRET)
diff --git a/tox.ini b/tox.ini
index 303b0d51d..d5cf8d2dc 100644
--- a/tox.ini
+++ b/tox.ini
@@ -5,10 +5,10 @@ envlist =
     docs,
     lint,
     sphinxlint,
-    py{38,39,310,311,312}-dj42,
-    py{310,311,312}-dj50,
-    py{310,311,312}-dj51,
-    py{310,311,312}-djmain,
+    py{38,39,310,311,312,313}-dj42,
+    py{310,311,312,313}-dj50,
+    py{310,311,312,313}-dj51,
+    py{310,311,312,313}-djmain,
     py39-multi-db-dj-42
 
 [gh-actions]
@@ -18,6 +18,7 @@ python =
     3.10: py310
     3.11: py311
     3.12: py312
+    3.13: py313
 
 [gh-actions:env]
 DJANGO =
@@ -54,7 +55,7 @@ deps =
 passenv =
     PYTEST_ADDOPTS
 
-[testenv:py{310,311,312}-djmain]
+[testenv:py{310,311,312,313}-djmain]
 ignore_errors = true
 ignore_outcome = true