diff --git a/gcloud/datastore/client.py b/gcloud/datastore/client.py
index 0dc60850f1eb..cb7c5a043ab5 100644
--- a/gcloud/datastore/client.py
+++ b/gcloud/datastore/client.py
@@ -395,9 +395,11 @@ def query(self, **kwargs):
 
         Passes our ``dataset_id``.
         """
+        if 'client' in kwargs:
+            raise TypeError('Cannot pass client')
         if 'dataset_id' in kwargs:
             raise TypeError('Cannot pass dataset_id')
         kwargs['dataset_id'] = self.dataset_id
         if 'namespace' not in kwargs:
             kwargs['namespace'] = self.namespace
-        return Query(**kwargs)
+        return Query(self, **kwargs)
diff --git a/gcloud/datastore/test_client.py b/gcloud/datastore/test_client.py
index a9fbc953ad29..611dad5f8845 100644
--- a/gcloud/datastore/test_client.py
+++ b/gcloud/datastore/test_client.py
@@ -667,6 +667,12 @@ def test_transaction(self):
         self.assertEqual(xact.args, (client,))
         self.assertEqual(xact.kwargs, {})
 
+    def test_query_w_client(self):
+        KIND = 'KIND'
+        client = self._makeOne()
+        other = self._makeOne()
+        self.assertRaises(TypeError, client.query, kind=KIND, client=other)
+
     def test_query_w_dataset_id(self):
         KIND = 'KIND'
         client = self._makeOne()
@@ -683,7 +689,7 @@ def test_query_w_defaults(self):
             query = client.query()
 
         self.assertTrue(isinstance(query, _Dummy))
-        self.assertEqual(query.args, ())
+        self.assertEqual(query.args, (client,))
         expected_kwargs = {
             'dataset_id': self.DATASET_ID,
             'namespace': None,
@@ -715,6 +721,7 @@ def test_query_explicit(self):
                 )
 
         self.assertTrue(isinstance(query, _Dummy))
+        self.assertEqual(query.args, (client,))
         kwargs = {
             'dataset_id': self.DATASET_ID,
             'kind': KIND,
@@ -725,7 +732,6 @@ def test_query_explicit(self):
             'order': ORDER,
             'group_by': GROUP_BY,
         }
-        self.assertEqual(query.args, ())
         self.assertEqual(query.kwargs, kwargs)
 
     def test_query_w_namespace(self):
@@ -739,7 +745,7 @@ def test_query_w_namespace(self):
             query = client.query(kind=KIND)
 
         self.assertTrue(isinstance(query, _Dummy))
-        self.assertEqual(query.args, ())
+        self.assertEqual(query.args, (client,))
         expected_kwargs = {
             'dataset_id': self.DATASET_ID,
             'namespace': NAMESPACE,
@@ -759,7 +765,7 @@ def test_query_w_namespace_collision(self):
             query = client.query(kind=KIND, namespace=NAMESPACE2)
 
         self.assertTrue(isinstance(query, _Dummy))
-        self.assertEqual(query.args, ())
+        self.assertEqual(query.args, (client,))
         expected_kwargs = {
             'dataset_id': self.DATASET_ID,
             'namespace': NAMESPACE2,
diff --git a/system_tests/datastore.py b/system_tests/datastore.py
index f9fedf146090..278640c5feb0 100644
--- a/system_tests/datastore.py
+++ b/system_tests/datastore.py
@@ -106,7 +106,7 @@ def test_post_with_generated_id(self):
         self._generic_test_post()
 
     def test_save_multiple(self):
-        with datastore.Transaction() as xact:
+        with client.transaction() as xact:
             entity1 = self._get_post()
             xact.put(entity1)
             # Register entity to be deleted.
@@ -131,7 +131,7 @@ def test_save_multiple(self):
         self.assertEqual(len(matches), 2)
 
     def test_empty_kind(self):
-        query = datastore.Query(kind='Post')
+        query = client.query(kind='Post')
         query.ancestor = self.PARENT
         posts = list(query.fetch(limit=2))
         self.assertEqual(posts, [])
@@ -149,7 +149,7 @@ def test_save_key_self_reference(self):
         client.put(entity)
         self.case_entities_to_delete.append(entity)
 
-        query = datastore.Query(kind='Person')
+        query = client.query(kind='Person')
         # Adding ancestor to ensure consistency.
         query.ancestor = parent_key
         query.add_filter('linkedTo', '=', key)
@@ -167,7 +167,7 @@ def setUpClass(cls):
         cls.ANCESTOR_KEY = datastore.Key(*populate_datastore.ANCESTOR)
 
     def _base_query(self):
-        return datastore.Query(kind='Character', ancestor=self.ANCESTOR_KEY)
+        return client.query(kind='Character', ancestor=self.ANCESTOR_KEY)
 
     def test_limit_queries(self):
         limit = 5
@@ -330,7 +330,7 @@ def test_transaction(self):
         entity = datastore.Entity(key=datastore.Key('Company', 'Google'))
         entity['url'] = u'www.google.com'
 
-        with datastore.Transaction() as xact:
+        with client.transaction() as xact:
             result = client.get(entity.key)
             if result is None:
                 xact.put(entity)