diff --git a/google/cloud/spanner_v1/client.py b/google/cloud/spanner_v1/client.py
index 52bc796431..e669fe8d27 100644
--- a/google/cloud/spanner_v1/client.py
+++ b/google/cloud/spanner_v1/client.py
@@ -409,7 +409,7 @@ def list_instances(self, filter_="", page_size=None, page_token=None):
         metadata = _metadata_with_prefix(self.project_name)
         path = "projects/%s" % (self.project,)
         page_iter = self.instance_admin_api.list_instances(
-            path, page_size=page_size, metadata=metadata
+            path, filter_=filter_, page_size=page_size, metadata=metadata
         )
         page_iter.item_to_value = self._item_to_instance
         page_iter.next_page_token = page_token
diff --git a/tests/unit/test_client.py b/tests/unit/test_client.py
index 7874ae68e9..4eab87ceb5 100644
--- a/tests/unit/test_client.py
+++ b/tests/unit/test_client.py
@@ -624,8 +624,9 @@ def test_list_instances_w_options(self):
         )
 
         token = "token"
+        filter = "name:instance"
         page_size = 42
-        list(client.list_instances(page_token=token, page_size=42))
+        list(client.list_instances(filter_=filter, page_token=token, page_size=42))
 
         expected_metadata = [
             ("google-cloud-resource-prefix", client.project_name),
@@ -633,7 +634,7 @@ def test_list_instances_w_options(self):
         ]
         li_api.assert_called_once_with(
             spanner_instance_admin_pb2.ListInstancesRequest(
-                parent=self.PATH, page_size=page_size, page_token=token
+                parent=self.PATH, filter=filter, page_size=page_size, page_token=token
             ),
             metadata=expected_metadata,
             retry=mock.ANY,