diff --git a/protos/hellostreamingworld.proto b/protos/hellostreamingworld.proto
index ec8405c..bd5af3b 100644
--- a/protos/hellostreamingworld.proto
+++ b/protos/hellostreamingworld.proto
@@ -30,6 +30,7 @@
 syntax = "proto3";
 
 option java_package = "ex.grpc";
+option objc_class_prefix = "HSW";
 
 package hellostreamingworld;
 
diff --git a/protos/helloworld.proto b/protos/helloworld.proto
index 6281c93..7d58870 100644
--- a/protos/helloworld.proto
+++ b/protos/helloworld.proto
@@ -30,6 +30,7 @@
 syntax = "proto3";
 
 option java_package = "io.grpc.examples";
+option objc_class_prefix = "HLW";
 
 package helloworld;
 
diff --git a/protos/route_guide.proto b/protos/route_guide.proto
index 3759049..bfde5f1 100644
--- a/protos/route_guide.proto
+++ b/protos/route_guide.proto
@@ -30,6 +30,7 @@
 syntax = "proto3";
 
 option java_package = "ex.grpc";
+option objc_class_prefix = "RTG";
 
 package examples;