diff --git a/dendrite-config.yaml b/dendrite-config.yaml
index b71e8d845..4d18a5636 100644
--- a/dendrite-config.yaml
+++ b/dendrite-config.yaml
@@ -142,6 +142,10 @@ client_api:
   # using the registration shared secret below.
   registration_disabled: false
 
+  # Prevents new guest accounts from being created. Guest registration is also
+  # disabled implicitly by setting 'registration_disabled' above.
+  guests_disabled: false
+
   # If set, allows registration by anyone who knows the shared secret, regardless of
   # whether registration is otherwise disabled.
   registration_shared_secret: ""