diff --git a/test/cpp/interop/client_helper.cc b/test/cpp/interop/client_helper.cc
index 65fdc63b43ccf2af6788e5bb1e2072b0252070d6..b8a222c54a0e6c48fbd453ce72e0269a58c8ccef 100644
--- a/test/cpp/interop/client_helper.cc
+++ b/test/cpp/interop/client_helper.cc
@@ -65,8 +65,6 @@ DECLARE_string(default_service_account);
 DECLARE_string(service_account_key_file);
 DECLARE_string(oauth_scope);
 
-using grpc::testing::CompressionType;
-
 namespace grpc {
 namespace testing {
 
@@ -143,20 +141,6 @@ std::shared_ptr<ChannelInterface> CreateChannelForTestCase(
   }
 }
 
-CompressionType GetInteropCompressionTypeFromCompressionAlgorithm(
-    grpc_compression_algorithm algorithm) {
-  switch (algorithm) {
-    case GRPC_COMPRESS_NONE:
-      return CompressionType::NONE;
-    case GRPC_COMPRESS_GZIP:
-      return CompressionType::GZIP;
-    case GRPC_COMPRESS_DEFLATE:
-      return CompressionType::DEFLATE;
-    default:
-      GPR_ASSERT(false);
-  }
-}
-
 InteropClientContextInspector::InteropClientContextInspector(
     const ::grpc::ClientContext& context)
     : context_(context) {}
diff --git a/test/cpp/interop/client_helper.h b/test/cpp/interop/client_helper.h
index 28fca3266cc1b4be12cd49a026470bca5319c007..000374ae8e375bb3518db2ec51a9ad879d33749e 100644
--- a/test/cpp/interop/client_helper.h
+++ b/test/cpp/interop/client_helper.h
@@ -39,8 +39,6 @@
 #include <grpc++/config.h>
 #include <grpc++/channel_interface.h>
 
-#include "test/proto/messages.grpc.pb.h"
-
 namespace grpc {
 namespace testing {
 
@@ -51,10 +49,6 @@ grpc::string GetOauth2AccessToken();
 std::shared_ptr<ChannelInterface> CreateChannelForTestCase(
     const grpc::string& test_case);
 
-grpc::testing::CompressionType
-GetInteropCompressionTypeFromCompressionAlgorithm(
-    grpc_compression_algorithm algorithm);
-
 class InteropClientContextInspector {
  public:
   InteropClientContextInspector(const ::grpc::ClientContext& context);
diff --git a/test/cpp/interop/interop_client.cc b/test/cpp/interop/interop_client.cc
index ddf91aa5eb1d58609653eacbeaab6cc3aafc7f16..9e738b6d3b44a70a5a437d6c7ccd28318b4ca9fd 100644
--- a/test/cpp/interop/interop_client.cc
+++ b/test/cpp/interop/interop_client.cc
@@ -67,6 +67,20 @@ const int kResponseMessageSize = 1030;
 const int kReceiveDelayMilliSeconds = 20;
 const int kLargeRequestSize = 271828;
 const int kLargeResponseSize = 314159;
+
+CompressionType GetInteropCompressionTypeFromCompressionAlgorithm(
+    grpc_compression_algorithm algorithm) {
+  switch (algorithm) {
+    case GRPC_COMPRESS_NONE:
+      return CompressionType::NONE;
+    case GRPC_COMPRESS_GZIP:
+      return CompressionType::GZIP;
+    case GRPC_COMPRESS_DEFLATE:
+      return CompressionType::DEFLATE;
+    default:
+      GPR_ASSERT(false);
+  }
+}
 }  // namespace
 
 InteropClient::InteropClient(std::shared_ptr<ChannelInterface> channel)