diff --git a/rtc_base/platform_thread_types.cc b/rtc_base/platform_thread_types.cc
index 15d48618bd..67bb0542e9 100644
--- a/rtc_base/platform_thread_types.cc
+++ b/rtc_base/platform_thread_types.cc
@@ -29,9 +29,11 @@ PlatformThreadId CurrentThreadId() {
   return zx_thread_self();
 #elif defined(WEBRTC_LINUX)
   return syscall(__NR_gettid);
+#elif defined(__EMSCRIPTEN__)
+  return static_cast<PlatformThreadId>(pthread_self());
 #else
   // Default implementation for nacl and solaris.
-  return reinterpret_cast<pid_t>(pthread_self());
+  return reinterpret_cast<PlatformThreadId>(pthread_self());
 #endif
 #endif  // defined(WEBRTC_POSIX)
 }
diff --git a/rtc_base/system/arch.h b/rtc_base/system/arch.h
index f07796bb52..eb77ffa8f4 100644
--- a/rtc_base/system/arch.h
+++ b/rtc_base/system/arch.h
@@ -47,6 +47,9 @@
 #elif defined(__pnacl__)
 #define WEBRTC_ARCH_32_BITS
 #define WEBRTC_ARCH_LITTLE_ENDIAN
+#elif defined(__EMSCRIPTEN__)
+#define WEBRTC_ARCH_32_BITS
+#define WEBRTC_ARCH_LITTLE_ENDIAN
 #else
 #error Please add support for your architecture in rtc_base/system/arch.h
 #endif