diff --git a/nova/conductor/manager.py b/nova/conductor/manager.py
index 1409720c914c..0240e62fafb9 100644
--- a/nova/conductor/manager.py
+++ b/nova/conductor/manager.py
@@ -1214,6 +1214,7 @@ class ComputeTaskManager(base.Base):
         host_mapping_cache = {}
         cell_mapping_cache = {}
         instances = []
+        host_az = {}  # host=az cache to optimize multi-create
 
         for (build_request, request_spec, host_list) in six.moves.zip(
                 build_requests, request_specs, host_lists):
@@ -1259,9 +1260,11 @@ class ComputeTaskManager(base.Base):
                 rc.delete_allocation_for_instance(context, instance.uuid)
                 continue
             else:
-                instance.availability_zone = (
-                    availability_zones.get_host_availability_zone(
-                        context, host.service_host))
+                if host.service_host not in host_az:
+                    host_az[host.service_host] = (
+                        availability_zones.get_host_availability_zone(
+                            context, host.service_host))
+                instance.availability_zone = host_az[host.service_host]
                 with obj_target_cell(instance, cell):
                     instance.create()
                     instances.append(instance)
diff --git a/nova/tests/unit/conductor/test_conductor.py b/nova/tests/unit/conductor/test_conductor.py
index 9e2ea4a455eb..84df38f9a2e3 100644
--- a/nova/tests/unit/conductor/test_conductor.py
+++ b/nova/tests/unit/conductor/test_conductor.py
@@ -1626,7 +1626,9 @@ class ConductorTaskTestCase(_BaseTaskTestCase, test_compute.BaseTestCase):
     @mock.patch('nova.compute.rpcapi.ComputeAPI.build_and_run_instance')
     @mock.patch('nova.scheduler.rpcapi.SchedulerAPI.select_destinations')
     @mock.patch('nova.objects.HostMapping.get_by_host')
-    def test_schedule_and_build_multiple_instances(self,
+    @mock.patch('nova.availability_zones.get_host_availability_zone',
+                return_value='nova')
+    def test_schedule_and_build_multiple_instances(self, mock_get_az,
                                                    get_hostmapping,
                                                    select_destinations,
                                                    build_and_run_instance):
@@ -1679,6 +1681,11 @@ class ConductorTaskTestCase(_BaseTaskTestCase, test_compute.BaseTestCase):
         build_and_run_instance.side_effect = _build_and_run_instance
         self.conductor.schedule_and_build_instances(**params)
         self.assertEqual(3, build_and_run_instance.call_count)
+        # We're processing 4 instances over 2 hosts, so we should only lookup
+        # the AZ per host once.
+        mock_get_az.assert_has_calls([
+            mock.call(self.ctxt, 'host1'), mock.call(self.ctxt, 'host2')],
+            any_order=True)
 
     @mock.patch('nova.compute.rpcapi.ComputeAPI.build_and_run_instance')
     @mock.patch('nova.scheduler.rpcapi.SchedulerAPI.select_destinations')