diff --git a/experimental/terraform/resource_event_handler.tf b/experimental/terraform/resource_event_handler.tf
index 4e8db47b..31fcac29 100644
--- a/experimental/terraform/resource_event_handler.tf
+++ b/experimental/terraform/resource_event_handler.tf
@@ -131,6 +131,6 @@ module "cloudbuild_for_publishing" {
   include       = ["event_handler/**"]
   substitutions = {
     _FOURKEYS_GCR_DOMAIN : "${var.google_region}-docker.pkg.dev"
-    _FOURKEYS_REGION : var.google_region
+    _FOURKEYS_REGION : length(var.mapped_domain) > 0 ? var.google_domain_mapping_region : var.google_region
   }
 }