diff --git a/core/google/cloud/operation.py b/core/google/cloud/operation.py
index 156212794487..f359496ba3cd 100644
--- a/core/google/cloud/operation.py
+++ b/core/google/cloud/operation.py
@@ -17,7 +17,7 @@
 from google.longrunning import operations_pb2
 
 
-_GOOGLE_APIS_PREFIX = 'types.googleapis.com'
+_GOOGLE_APIS_PREFIX = 'type.googleapis.com'
 
 _TYPE_URL_MAP = {
 }