diff --git a/containers/mautrix-facebook.yaml b/containers/mautrix-facebook.yaml
index 6dc9361..b5f2f34 100644
--- a/containers/mautrix-facebook.yaml
+++ b/containers/mautrix-facebook.yaml
@@ -323,6 +323,8 @@ facebook:
     carrier: Verizon
     hni: 311390
 
+env_prefix: "MAUTRIX_FACEBOOK"
+
 # Python logging configuration.
 #
 # See section 16.7.2 of the Python documentation for more info: