diff --git a/src/tests/DawnTest.cpp b/src/tests/DawnTest.cpp
index 8df1cd8..4d9a09e 100644
--- a/src/tests/DawnTest.cpp
+++ b/src/tests/DawnTest.cpp
@@ -19,6 +19,7 @@
 #include "common/Log.h"
 #include "common/Math.h"
 #include "common/Platform.h"
+#include "common/SystemUtils.h"
 #include "dawn/dawn_proc.h"
 #include "dawn_native/DawnNative.h"
 #include "dawn_wire/WireClient.h"
@@ -28,6 +29,7 @@
 #include "utils/WGPUHelpers.h"
 
 #include <algorithm>
+#include <fstream>
 #include <iomanip>
 #include <sstream>
 #include <unordered_map>
@@ -158,6 +160,19 @@
             continue;
         }
 
+        constexpr const char kWireTraceDirArg[] = "--wire-trace-dir=";
+        if (strstr(argv[i], kWireTraceDirArg) == argv[i]) {
+            const char* wireTraceDir = argv[i] + strlen(kWireTraceDirArg);
+            if (wireTraceDir[0] != '\0') {
+                const char* sep = GetPathSeparator();
+                mWireTraceDir = wireTraceDir;
+                if (mWireTraceDir.back() != *sep) {
+                    mWireTraceDir += sep;
+                }
+            }
+            continue;
+        }
+
         if (strcmp("-h", argv[i]) == 0 || strcmp("--help", argv[i]) == 0) {
             dawn::InfoLog()
                 << "\n\nUsage: " << argv[0]
@@ -264,6 +279,13 @@
     return mVendorIdFilter;
 }
 
+const char* DawnTestEnvironment::GetWireTraceDir() const {
+    if (mWireTraceDir.length() == 0) {
+        return nullptr;
+    }
+    return mWireTraceDir.c_str();
+}
+
 void DawnTestEnvironment::DiscoverOpenGLAdapter() {
 #ifdef DAWN_ENABLE_BACKEND_OPENGL
     if (!glfwInit()) {
@@ -285,6 +307,23 @@
 #endif  // DAWN_ENABLE_BACKEND_OPENGL
 }
 
+class WireServerTraceLayer : public dawn_wire::CommandHandler {
+  public:
+    WireServerTraceLayer(const char* file, dawn_wire::WireServer* server)
+        : dawn_wire::CommandHandler(), mServer(server) {
+        mFile.open(file, std::ios_base::app | std::ios_base::binary | std::ios_base::trunc);
+    }
+
+    const volatile char* HandleCommands(const volatile char* commands, size_t size) override {
+        mFile.write(const_cast<const char*>(commands), size);
+        return mServer->HandleCommands(commands, size);
+    }
+
+  private:
+    dawn_wire::WireServer* mServer;
+    std::ofstream mFile;
+};
+
 // Implementation of DawnTest
 
 DawnTestBase::DawnTestBase(const DawnTestParam& param) : mParam(param) {
@@ -497,6 +536,21 @@
         mWireServer.reset(new dawn_wire::WireServer(serverDesc));
         mC2sBuf->SetHandler(mWireServer.get());
 
+        if (gTestEnv->GetWireTraceDir() != nullptr) {
+            std::string file =
+                std::string(
+                    ::testing::UnitTest::GetInstance()->current_test_info()->test_suite_name()) +
+                "_" + ::testing::UnitTest::GetInstance()->current_test_info()->name();
+            // Replace slashes in gtest names with underscores so everything is in one directory.
+            std::replace(file.begin(), file.end(), '/', '_');
+
+            std::string fullPath = gTestEnv->GetWireTraceDir() + file;
+
+            mWireServerTraceLayer.reset(
+                new WireServerTraceLayer(fullPath.c_str(), mWireServer.get()));
+            mC2sBuf->SetHandler(mWireServerTraceLayer.get());
+        }
+
         dawn_wire::WireClientDescriptor clientDesc = {};
         clientDesc.serializer = mC2sBuf.get();
 
diff --git a/src/tests/DawnTest.h b/src/tests/DawnTest.h
index 3f23d4e..d7e88a6 100644
--- a/src/tests/DawnTest.h
+++ b/src/tests/DawnTest.h
@@ -117,6 +117,7 @@
 }  // namespace detail
 
 namespace dawn_wire {
+    class CommandHandler;
     class WireClient;
     class WireServer;
 }  // namespace dawn_wire
@@ -140,6 +141,7 @@
     dawn_native::Instance* GetInstance() const;
     bool HasVendorIdFilter() const;
     uint32_t GetVendorIdFilter() const;
+    const char* GetWireTraceDir() const;
 
   protected:
     std::unique_ptr<dawn_native::Instance> mInstance;
@@ -154,6 +156,7 @@
     bool mBeginCaptureOnStartup = false;
     bool mHasVendorIdFilter = false;
     uint32_t mVendorIdFilter = 0;
+    std::string mWireTraceDir;
 };
 
 class DawnTestBase {
@@ -242,6 +245,8 @@
     std::unique_ptr<utils::TerribleCommandBuffer> mC2sBuf;
     std::unique_ptr<utils::TerribleCommandBuffer> mS2cBuf;
 
+    std::unique_ptr<dawn_wire::CommandHandler> mWireServerTraceLayer;
+
     // Tracking for validation errors
     static void OnDeviceError(WGPUErrorType type, const char* message, void* userdata);
     bool mExpectError = false;