diff --git a/.github/workflows/clang-tidy.yaml b/.github/workflows/clang-tidy.yaml
index 48a3cc8d60..3d296602b8 100644
--- a/.github/workflows/clang-tidy.yaml
+++ b/.github/workflows/clang-tidy.yaml
@@ -17,9 +17,9 @@ jobs:
       matrix:
         include:
           - cmake_options: all-options-abiv1-preview
-            warning_limit: 151
+            warning_limit: 142
           - cmake_options: all-options-abiv2-preview
-            warning_limit: 161
+            warning_limit: 152
     env:
       CC: /usr/bin/clang-22
       CXX: /usr/bin/clang++-22
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 55405b8d55..8baba4503c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -15,6 +15,10 @@ Increment the:
 
 ## [Unreleased]
 
+* [CODE HEALTH] Move SDK trace and metrics test helpers into anonymous
+  namespaces
+  [#4303](https://github.com/open-telemetry/opentelemetry-cpp/pull/4303)
+
 * [CODE HEALTH] Move metrics storage test fixtures into anonymous namespace
   [#4286](https://github.com/open-telemetry/opentelemetry-cpp/pull/4286)
 
diff --git a/sdk/test/metrics/exemplar/aligned_histogram_bucket_exemplar_reservoir_test.cc b/sdk/test/metrics/exemplar/aligned_histogram_bucket_exemplar_reservoir_test.cc
index ee1eb72cce..d6effcef3d 100644
--- a/sdk/test/metrics/exemplar/aligned_histogram_bucket_exemplar_reservoir_test.cc
+++ b/sdk/test/metrics/exemplar/aligned_histogram_bucket_exemplar_reservoir_test.cc
@@ -23,6 +23,9 @@ namespace sdk
 {
 namespace metrics
 {
+namespace
+{
+
 class AlignedHistogramBucketExemplarReservoirTestPeer : public ::testing::Test
 {
 public:
@@ -59,6 +62,8 @@ TEST_F(AlignedHistogramBucketExemplarReservoirTestPeer, OfferMeasurementWithNonE
   ASSERT_TRUE(!exemplar_data.empty());
 }
 
+}  // namespace
+
 }  // namespace metrics
 }  // namespace sdk
 OPENTELEMETRY_END_NAMESPACE
diff --git a/sdk/test/metrics/measurements_benchmark.cc b/sdk/test/metrics/measurements_benchmark.cc
index 75a5c34d14..0dee405448 100644
--- a/sdk/test/metrics/measurements_benchmark.cc
+++ b/sdk/test/metrics/measurements_benchmark.cc
@@ -35,6 +35,9 @@ using namespace opentelemetry::sdk::instrumentationscope;
 using namespace opentelemetry::sdk::metrics;
 using namespace opentelemetry::sdk::common;
 
+namespace
+{
+
 class MockMetricExporter : public MetricReader
 {
 public:
@@ -54,9 +57,6 @@ class MockMetricExporter : public MetricReader
   void OnInitialized() noexcept override {}
 };
 
-namespace
-{
-
 size_t GetBenchmarkThreads()
 {
   const char *env = std::getenv("BENCHMARK_THREADS");
diff --git a/sdk/test/trace/batch_span_processor_test.cc b/sdk/test/trace/batch_span_processor_test.cc
index 49c8d8b4e2..ba4551b03f 100644
--- a/sdk/test/trace/batch_span_processor_test.cc
+++ b/sdk/test/trace/batch_span_processor_test.cc
@@ -32,6 +32,9 @@ using opentelemetry::sdk::common::unsetenv;
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 
+namespace
+{
+
 /**
  * Returns a mock span exporter meant exclusively for testing only
  */
@@ -499,4 +502,6 @@ TEST(BatchSpanProcessorOptionsEnvTest, TestDesignatedInitializers)
 }
 #endif
 
+}  // namespace
+
 OPENTELEMETRY_END_NAMESPACE
diff --git a/sdk/test/trace/tracer_provider_set_test.cc b/sdk/test/trace/tracer_provider_set_test.cc
index 3991582264..d6d6828d26 100644
--- a/sdk/test/trace/tracer_provider_set_test.cc
+++ b/sdk/test/trace/tracer_provider_set_test.cc
@@ -24,6 +24,9 @@ namespace nostd     = opentelemetry::nostd;
 namespace trace_api = opentelemetry::trace;
 namespace trace_sdk = opentelemetry::sdk::trace;
 
+namespace
+{
+
 class TestProvider : public TracerProvider
 {
 public:
@@ -80,3 +83,5 @@ TEST(Provider, SetTracerProviderDisabled)
   unsetenv("OTEL_SDK_DISABLED");
 }
 #endif
+
+}  // namespace
diff --git a/sdk/test/trace/tracer_test.cc b/sdk/test/trace/tracer_test.cc
index d3107db47a..86114c44a2 100644
--- a/sdk/test/trace/tracer_test.cc
+++ b/sdk/test/trace/tracer_test.cc
@@ -67,6 +67,9 @@ using opentelemetry::exporter::memory::InMemorySpanData;
 using opentelemetry::exporter::memory::InMemorySpanExporter;
 using opentelemetry::trace::SpanContext;
 
+namespace
+{
+
 /**
  * A mock sampler with ShouldSample returning:
  *  Decision::RECORD_AND_SAMPLE if trace_id is valid
@@ -171,8 +174,6 @@ class MockIdGenerator : public IdGenerator
   uint8_t buf_trace[16] = {1, 2, 3, 4, 5, 6, 7, 8, 8, 7, 6, 5, 4, 3, 2, 1};
 };
 
-namespace
-{
 std::shared_ptr<opentelemetry::trace::Tracer> initTracer(std::unique_ptr<SpanExporter> &&exporter)
 {
   auto processor = std::unique_ptr<SpanProcessor>(new SimpleSpanProcessor(std::move(exporter)));