diff --git a/build/scripts/ComplementLocal.Dockerfile b/build/scripts/ComplementLocal.Dockerfile
index a9feb4cd1..520c3ca69 100644
--- a/build/scripts/ComplementLocal.Dockerfile
+++ b/build/scripts/ComplementLocal.Dockerfile
@@ -30,7 +30,7 @@ RUN echo '\
 #!/bin/bash -eu \n\
 ./generate-keys --private-key matrix_key.pem \n\
 ./generate-keys --server $SERVER_NAME --tls-cert server.crt --tls-key server.key --tls-authority-cert /complement/ca/ca.crt --tls-authority-key /complement/ca/ca.key \n\
-./generate-config -server $SERVER_NAME --ci > dendrite.yaml \n\
+./generate-config -server $SERVER_NAME --ci | sed -e "s;https://accounts.google.com/;${FAKE_SSO_URL:-https://accounts.google.com/};" > dendrite.yaml \n\
 cp /complement/ca/ca.crt /usr/local/share/ca-certificates/ && update-ca-certificates \n\
 ./dendrite-monolith-server --really-enable-open-registration --tls-cert server.crt --tls-key server.key --config dendrite.yaml \n\
 ' > run.sh && chmod +x run.sh