diff --git a/cubedash/_stac.py b/cubedash/_stac.py
index 4b8e6d248..b33287d79 100644
--- a/cubedash/_stac.py
+++ b/cubedash/_stac.py
@@ -579,6 +579,13 @@ def _handle_search_request(
                     "Only 'id', 'collection', and Item properties can be used to sort results.",
                 )
 
+    # Make sure users know that the query extension isn't implemented
+    if request_args.get("query") is not None:
+        abort(
+            400,
+            "The Query extension is no longer supported. Please use the Filter extension instead.",
+        )
+
     filter_lang = request_args.get("filter-lang", default=None, type=str)
     filter_cql = request_args.get("filter", default=None, type=_filter_arg)
     filter_crs = request_args.get("filter-crs", default=None)
diff --git a/integration_tests/test_stac.py b/integration_tests/test_stac.py
index 26a7272eb..ec23a2afa 100644
--- a/integration_tests/test_stac.py
+++ b/integration_tests/test_stac.py
@@ -1544,3 +1544,22 @@ def test_stac_filter_extension(stac_client: FlaskClient):
         headers={"Content-Type": "application/json", "Accept": "application/json"},
     )
     assert rv.status_code == 400
+
+
+def test_stac_query_extension_errors(stac_client: FlaskClient):
+    # Trying to use query extension should error
+    query = {"cloud_cover": {"lt": 1}}
+    rv: Response = stac_client.post(
+        "/stac/search",
+        data=json.dumps(
+            {
+                "product": "ga_ls8c_ard_3",
+                "time": "2022-01-01T00:00:00/2022-12-31T00:00:00",
+                "limit": OUR_DATASET_LIMIT,
+                "_full": True,
+                "query": query,
+            }
+        ),
+        headers={"Content-Type": "application/json", "Accept": "application/json"},
+    )
+    assert rv.status_code == 400