diff --git a/synapse/config/voip.py b/synapse/config/voip.py
index a2b822719..65162d21b 100644
--- a/synapse/config/voip.py
+++ b/synapse/config/voip.py
@@ -28,7 +28,7 @@ class VoipConfig(Config):
         super(VoipConfig, cls).add_arguments(parser)
         group = parser.add_argument_group("voip")
         group.add_argument(
-            "--turn-uris", type=str, default=None,
+            "--turn-uris", type=str, default=None, action='append',
             help="The public URIs of the TURN server to give to clients"
         )
         group.add_argument(