diff --git a/compose/config/config.py b/compose/config/config.py
index 27f5ff6a2..2faa12b2d 100644
--- a/compose/config/config.py
+++ b/compose/config/config.py
@@ -698,6 +698,7 @@ def merge_service_dicts(base, override, version):
         'depends_on',
         'expose',
         'external_links',
+        'networks',
         'ports',
         'volumes_from',
     ]: