diff --git a/src/google/protobuf/unittest_drop_unknown_fields.proto b/src/google/protobuf/unittest_drop_unknown_fields.proto
index a8a98ad394..d6a8cc740d 100644
--- a/src/google/protobuf/unittest_drop_unknown_fields.proto
+++ b/src/google/protobuf/unittest_drop_unknown_fields.proto
@@ -32,7 +32,6 @@ syntax = "proto3";
 
 package unittest_drop_unknown_fields;
 
-option objc_class_prefix = "DropUnknowns";
 option csharp_namespace = "Google.Protobuf.TestProtos";
 
 message Foo {
diff --git a/src/google/protobuf/unittest_preserve_unknown_enum.proto b/src/google/protobuf/unittest_preserve_unknown_enum.proto
index 2f91332c9e..f73b764aa1 100644
--- a/src/google/protobuf/unittest_preserve_unknown_enum.proto
+++ b/src/google/protobuf/unittest_preserve_unknown_enum.proto
@@ -31,7 +31,6 @@
 syntax = "proto3";
 
 package proto3_preserve_unknown_enum_unittest;
-option objc_class_prefix = "UnknownEnums";
 
 option csharp_namespace = "Google.Protobuf.TestProtos";