diff --git a/gapic-common/lib/gapic/rest.rb b/gapic-common/lib/gapic/rest.rb
index 474ce2634..4db4a8203 100644
--- a/gapic-common/lib/gapic/rest.rb
+++ b/gapic-common/lib/gapic/rest.rb
@@ -29,4 +29,5 @@
 require "gapic/rest/paged_enumerable"
 require "gapic/rest/server_stream"
 require "gapic/rest/threaded_enumerator"
+require "gapic/rest/transport_operation"
 require "json"