diff --git a/src/objective-c/tests/run_tests.sh b/src/objective-c/tests/run_tests.sh
index a265149f488a362971acd399fb3633e777bdefc2..81c2885320512e2d89db2663e8c0bfdf9bd45133 100755
--- a/src/objective-c/tests/run_tests.sh
+++ b/src/objective-c/tests/run_tests.sh
@@ -44,8 +44,8 @@ BINDIR=../../../bins/$CONFIG
              "interop_server before calling this script."
     exit 1
 }
-$BINDIR/interop_server --port=5050 &
-$BINDIR/interop_server --port=5051 --use_tls &
+$BINDIR/interop_server --port=5050 --max_send_message_size=8388608 &
+$BINDIR/interop_server --port=5051 --max_send_message_size=8388608 --use_tls &
 # Kill them when this script exits.
 trap 'kill -9 `jobs -p`' EXIT
 
diff --git a/test/cpp/interop/interop_server.cc b/test/cpp/interop/interop_server.cc
index e5878bb248c8fecd75bac0cddafbe9bc59233368..c05eb5d1461be32918df80dfd59606f01510999b 100644
--- a/test/cpp/interop/interop_server.cc
+++ b/test/cpp/interop/interop_server.cc
@@ -56,6 +56,7 @@
 
 DEFINE_bool(use_tls, false, "Whether to use tls.");
 DEFINE_int32(port, 0, "Server port.");
+DEFINE_int32(max_send_message_size, -1, "The maximum send message size.");
 
 using grpc::Server;
 using grpc::ServerBuilder;
@@ -321,6 +322,9 @@ void grpc::testing::interop::RunServer(
   ServerBuilder builder;
   builder.RegisterService(&service);
   builder.AddListeningPort(server_address.str(), creds);
+  if (FLAGS_max_send_message_size >= 0) {
+    builder.SetMaxSendMessageSize(FLAGS_max_send_message_size);
+  }
   std::unique_ptr<Server> server(builder.BuildAndStart());
   gpr_log(GPR_INFO, "Server listening on %s", server_address.str().c_str());
   while (!g_got_sigint) {