diff --git a/test/core/call/bm_client_call.cc b/test/core/call/bm_client_call.cc
index 964e86af915..aefe7a6c8b5 100644
--- a/test/core/call/bm_client_call.cc
+++ b/test/core/call/bm_client_call.cc
@@ -26,6 +26,7 @@
 #include "src/core/lib/transport/call_arena_allocator.h"
 
 namespace grpc_core {
+namespace {
 
 class TestCallDestination : public UnstartedCallDestination {
  public:
@@ -170,6 +171,7 @@ void BM_Unary(benchmark::State& state) {
 }
 BENCHMARK(BM_Unary);
 
+}  // namespace
 }  // namespace grpc_core
 
 // Some distros have RunSpecifiedBenchmarks under the benchmark namespace,
diff --git a/test/core/client_channel/bm_client_channel.cc b/test/core/client_channel/bm_client_channel.cc
index d3ef834b207..f3d56b6ea8e 100644
--- a/test/core/client_channel/bm_client_channel.cc
+++ b/test/core/client_channel/bm_client_channel.cc
@@ -25,7 +25,9 @@
 
 namespace grpc_core {
 
+namespace {
 const Slice kTestPath = Slice::FromExternalString("/foo/bar");
+}
 
 class ClientChannelTraits {
  public:
@@ -110,6 +112,7 @@ class ClientChannelTraits {
 };
 GRPC_CALL_SPINE_BENCHMARK(UnstartedCallDestinationFixture<ClientChannelTraits>);
 
+namespace {
 class TestResolver final : public Resolver {
  public:
   explicit TestResolver(ChannelArgs args,
@@ -171,6 +174,7 @@ void BM_CreateClientChannel(benchmark::State& state) {
 }
 BENCHMARK(BM_CreateClientChannel);
 
+}  // namespace
 }  // namespace grpc_core
 
 // Some distros have RunSpecifiedBenchmarks under the benchmark namespace,
diff --git a/test/core/transport/bm_call_spine.cc b/test/core/transport/bm_call_spine.cc
index 3a99dad67b6..8a6bacdc427 100644
--- a/test/core/transport/bm_call_spine.cc
+++ b/test/core/transport/bm_call_spine.cc
@@ -100,6 +100,7 @@ class ForwardCallFixture {
       CallFilters::StackBuilder().Build();
 };
 GRPC_CALL_SPINE_BENCHMARK(ForwardCallFixture);
+
 }  // namespace grpc_core
 
 // Some distros have RunSpecifiedBenchmarks under the benchmark namespace,