diff --git a/contrib/docker/docker-compose.yml b/contrib/docker/docker-compose.yml
index 1d2aebbcd3..46e72601d3 100644
--- a/contrib/docker/docker-compose.yml
+++ b/contrib/docker/docker-compose.yml
@@ -15,6 +15,7 @@ services:
       - SYNAPSE_SERVER_NAME=my.matrix.host
       - SYNAPSE_REPORT_STATS=no
       - SYNAPSE_ENABLE_REGISTRATION=yes
+      - POSTGRES_PASSWORD=changeme
     volumes:
       # You may either store all the files in a local folder
       - ./files:/data