diff --git a/include/bx/cpu.h b/include/bx/cpu.h
index 70379ec..483d935 100644
--- a/include/bx/cpu.h
+++ b/include/bx/cpu.h
@@ -62,6 +62,8 @@ namespace bx
 	{
 #if BX_PLATFORM_XBOX360
 		__lwsync();
+#elif BX_PLATFORM_WINRT
+        MemoryBarrier();
 #elif BX_COMPILER_MSVC
 		_mm_mfence();
 #else
diff --git a/include/bx/debug.h b/include/bx/debug.h
index 2f58bbd..6a87c14 100644
--- a/include/bx/debug.h
+++ b/include/bx/debug.h
@@ -10,7 +10,7 @@
 
 #if BX_PLATFORM_ANDROID
 #	include <android/log.h>
-#elif BX_PLATFORM_WINDOWS || BX_PLATFORM_XBOX360
+#elif BX_PLATFORM_WINDOWS || BX_PLATFORM_XBOX360 || BX_PLATFORM_WINRT
 extern "C" __declspec(dllimport) void __stdcall OutputDebugStringA(const char* _str);
 #elif BX_PLATFORM_IOS || BX_PLATFORM_OSX
 #	if defined(__OBJC__)
@@ -47,7 +47,7 @@ namespace bx
 	{
 #if BX_PLATFORM_ANDROID
 		__android_log_write(ANDROID_LOG_DEBUG, "", _out);
-#elif BX_PLATFORM_WINDOWS || BX_PLATFORM_XBOX360
+#elif BX_PLATFORM_WINDOWS || BX_PLATFORM_XBOX360 || BX_PLATFORM_WINRT
 		OutputDebugStringA(_out);
 #elif BX_PLATFORM_IOS || BX_PLATFORM_OSX
 #	if defined(__OBJC__)
diff --git a/include/bx/macros.h b/include/bx/macros.h
index fc1747e..3aa481f 100644
--- a/include/bx/macros.h
+++ b/include/bx/macros.h
@@ -171,7 +171,7 @@
 #endif // BX_CONFIG_SEMAPHORE_PTHREAD
 
 #ifndef BX_CONFIG_SUPPORTS_THREADING
-#	define BX_CONFIG_SUPPORTS_THREADING !BX_PLATFORM_EMSCRIPTEN
+#	define BX_CONFIG_SUPPORTS_THREADING !(BX_PLATFORM_EMSCRIPTEN || BX_PLATFORM_WINRT)
 #endif // BX_CONFIG_SUPPORTS_THREADING
 
 #endif // BX_MACROS_H_HEADER_GUARD
diff --git a/include/bx/mutex.h b/include/bx/mutex.h
index 903babd..bb09059 100644
--- a/include/bx/mutex.h
+++ b/include/bx/mutex.h
@@ -14,13 +14,13 @@
 
 #if BX_PLATFORM_NACL || BX_PLATFORM_LINUX || BX_PLATFORM_ANDROID || BX_PLATFORM_OSX
 #	include <pthread.h>
-#elif BX_PLATFORM_WINDOWS || BX_PLATFORM_XBOX360
+#elif BX_PLATFORM_WINDOWS || BX_PLATFORM_XBOX360 || BX_PLATFORM_WINRT
 #	include <errno.h>
 #endif // BX_PLATFORM_
 
 namespace bx
 {
-#if BX_PLATFORM_WINDOWS || BX_PLATFORM_XBOX360
+#if BX_PLATFORM_WINDOWS || BX_PLATFORM_XBOX360 || BX_PLATFORM_WINRT
 	typedef CRITICAL_SECTION pthread_mutex_t;
 	typedef unsigned pthread_mutexattr_t;
 
@@ -43,7 +43,11 @@ namespace bx
 
 	inline int pthread_mutex_init(pthread_mutex_t* _mutex, pthread_mutexattr_t* /*_attr*/)
 	{
+#if BX_PLATFORM_WINRT
+        InitializeCriticalSectionEx(_mutex, 4000, 0);   // docs recommend 4000 spincount as sane default
+#else
 		InitializeCriticalSection(_mutex);
+#endif
 		return 0;
 	}
 
diff --git a/include/bx/os.h b/include/bx/os.h
index 9f412c7..4ab5c2b 100644
--- a/include/bx/os.h
+++ b/include/bx/os.h
@@ -8,7 +8,7 @@
 
 #include "bx.h"
 
-#if BX_PLATFORM_WINDOWS
+#if BX_PLATFORM_WINDOWS || BX_PLATFORM_WINRT
 #	include <windows.h>
 #elif BX_PLATFORM_ANDROID \
 	|| BX_PLATFORM_EMSCRIPTEN \
@@ -52,6 +52,9 @@ namespace bx
 	{
 #if BX_PLATFORM_WINDOWS || BX_PLATFORM_XBOX360
 		::Sleep(_ms);
+#elif BX_PLATFORM_WINRT
+        BX_UNUSED(_ms);
+        debugOutput("sleep is not implemented"); debugBreak();
 #else
 		timespec req = {(time_t)_ms/1000, (long)((_ms%1000)*1000000)};
 		timespec rem = {0, 0};
@@ -65,6 +68,8 @@ namespace bx
 		::SwitchToThread();
 #elif BX_PLATFORM_XBOX360
 		::Sleep(0);
+#elif BX_PLATFORM_WINRT
+        debugOutput("yield is not implemented"); debugBreak();
 #else
 		::sched_yield();
 #endif // BX_PLATFORM_
@@ -92,7 +97,7 @@ namespace bx
 	{
 #if BX_PLATFORM_WINDOWS
 		return (void*)::LoadLibraryA(_filePath);
-#elif BX_PLATFORM_NACL || BX_PLATFORM_EMSCRIPTEN
+#elif BX_PLATFORM_NACL || BX_PLATFORM_EMSCRIPTEN || BX_PLATFORM_WINRT
 		BX_UNUSED(_filePath);
 		return NULL;
 #else
@@ -104,7 +109,7 @@ namespace bx
 	{
 #if BX_PLATFORM_WINDOWS
 		::FreeLibrary( (HMODULE)_handle);
-#elif BX_PLATFORM_NACL || BX_PLATFORM_EMSCRIPTEN
+#elif BX_PLATFORM_NACL || BX_PLATFORM_EMSCRIPTEN || BX_PLATFORM_WINRT
 		BX_UNUSED(_handle);
 #else
 		::dlclose(_handle);
@@ -115,7 +120,7 @@ namespace bx
 	{
 #if BX_PLATFORM_WINDOWS
 		return (void*)::GetProcAddress( (HMODULE)_handle, _symbol);
-#elif BX_PLATFORM_NACL || BX_PLATFORM_EMSCRIPTEN
+#elif BX_PLATFORM_NACL || BX_PLATFORM_EMSCRIPTEN || BX_PLATFORM_WINRT
 		BX_UNUSED(_handle, _symbol);
 		return NULL;
 #else
@@ -127,6 +132,8 @@ namespace bx
 	{
 #if BX_PLATFORM_WINDOWS
 		::SetEnvironmentVariableA(_name, _value);
+#elif BX_PLATFORM_WINRT
+        BX_UNUSED(_name, _value);
 #else
 		::setenv(_name, _value, 1);
 #endif // BX_PLATFORM_
@@ -136,6 +143,8 @@ namespace bx
 	{
 #if BX_PLATFORM_WINDOWS
 		::SetEnvironmentVariableA(_name, NULL);
+#elif BX_PLATFORM_WINRT
+        BX_UNUSED(_name);
 #else
 		::unsetenv(_name);
 #endif // BX_PLATFORM_
@@ -143,7 +152,9 @@ namespace bx
 
 	inline int chdir(const char* _path)
 	{
-#if BX_COMPILER_MSVC
+#if BX_PLATFORM_WINRT
+        BX_UNUSED(_path);
+#elif BX_COMPILER_MSVC
 		return ::_chdir(_path);
 #else
 		return ::chdir(_path);
@@ -152,7 +163,9 @@ namespace bx
 
 	inline char* pwd(char* _buffer, uint32_t _size)
 	{
-#if BX_COMPILER_MSVC
+#if BX_PLATFORM_WINRT
+        BX_UNUSED(_buffer, _size);
+#elif BX_COMPILER_MSVC
 		return ::_getcwd(_buffer, (int)_size);
 #else
 		return ::getcwd(_buffer, _size);
diff --git a/include/bx/platform.h b/include/bx/platform.h
index a2eb196..bb88ca5 100644
--- a/include/bx/platform.h
+++ b/include/bx/platform.h
@@ -19,6 +19,7 @@
 #define BX_PLATFORM_OSX 0
 #define BX_PLATFORM_QNX 0
 #define BX_PLATFORM_WINDOWS 0
+#define BX_PLATFORM_WINRT 0
 #define BX_PLATFORM_XBOX360 0
 
 #define BX_CPU_ARM  0
@@ -53,14 +54,19 @@
 #	undef BX_PLATFORM_XBOX360
 #	define BX_PLATFORM_XBOX360 1
 #elif defined(_WIN32) || defined(_WIN64)
-#	undef BX_PLATFORM_WINDOWS
 // http://msdn.microsoft.com/en-us/library/6sehtctf.aspx
-#	if !defined(WINVER) && !defined(_WIN32_WINNT)
-// Windows Server 2003 with SP1, Windows XP with SP2 and above
-#		define WINVER 0x0502
-#		define _WIN32_WINNT 0x0502
-#	endif // !defined(WINVER) && !defined(_WIN32_WINNT)
-#	define BX_PLATFORM_WINDOWS _WIN32_WINNT
+#   if !defined(WINAPI_FAMILY) || (WINAPI_FAMILY == WINAPI_FAMILY_DESKTOP_APP)
+#	    undef BX_PLATFORM_WINDOWS
+#	    if !defined(WINVER) && !defined(_WIN32_WINNT)
+        // Windows Server 2003 with SP1, Windows XP with SP2 and above
+#		    define WINVER 0x0502
+#		    define _WIN32_WINNT 0x0502
+#	    endif // !defined(WINVER) && !defined(_WIN32_WINNT)
+#	    define BX_PLATFORM_WINDOWS _WIN32_WINNT
+#   else
+#       undef BX_PLATFORM_WINRT
+#       define BX_PLATFORM_WINRT 1
+#   endif
 #elif defined(__native_client__)
 // NaCl compiler defines __linux__
 #	undef BX_PLATFORM_NACL
@@ -103,7 +109,7 @@
 						)
 
 // http://sourceforge.net/apps/mediawiki/predef/index.php?title=Architectures
-#if defined(__arm__)
+#if defined(__arm__) || (defined(WINAPI_FAMILY) && (WINAPI_FAMILY == WINAPI_FAMILY_PHONE_APP))
 #	undef BX_CPU_ARM
 #	define BX_CPU_ARM 1
 #	define BX_CACHE_LINE_SIZE 64
@@ -171,6 +177,8 @@
 #	define BX_PLATFORM_NAME "QNX"
 #elif BX_PLATFORM_WINDOWS
 #	define BX_PLATFORM_NAME "Windows"
+#elif BX_PLATFORM_WINRT
+#   define BX_PLATFORM_NAME "WinRT"
 #endif // BX_PLATFORM_
 
 #if BX_CPU_ARM
diff --git a/include/bx/sem.h b/include/bx/sem.h
index 50e150b..dcfe654 100644
--- a/include/bx/sem.h
+++ b/include/bx/sem.h
@@ -16,7 +16,7 @@
 #	include <semaphore.h>
 #	include <time.h>
 #	include <pthread.h>
-#elif BX_PLATFORM_WINDOWS || BX_PLATFORM_XBOX360
+#elif BX_PLATFORM_WINDOWS || BX_PLATFORM_XBOX360 || BX_PLATFORM_WINRT
 #	include <windows.h>
 #	include <limits.h>
 #endif // BX_PLATFORM_
@@ -190,7 +190,7 @@ namespace bx
 	};
 #	endif // BX_CONFIG_SEMAPHORE_PTHREAD
 
-#elif BX_PLATFORM_WINDOWS || BX_PLATFORM_XBOX360
+#elif BX_PLATFORM_WINDOWS || BX_PLATFORM_XBOX360 || BX_PLATFORM_WINRT
 
 	class Semaphore
 	{
diff --git a/include/bx/timer.h b/include/bx/timer.h
index 71603a7..2efb8ac 100644
--- a/include/bx/timer.h
+++ b/include/bx/timer.h
@@ -14,7 +14,7 @@
 #	include <emscripten.h>
 #elif  BX_PLATFORM_FREEBSD || BX_PLATFORM_LINUX || BX_PLATFORM_NACL || BX_PLATFORM_OSX || BX_PLATFORM_IOS || BX_PLATFORM_QNX
 #	include <sys/time.h> // gettimeofday
-#elif BX_PLATFORM_WINDOWS
+#elif BX_PLATFORM_WINDOWS || BX_PLATFORM_WINRT
 #	include <windows.h>
 #endif // BX_PLATFORM_
 
@@ -22,7 +22,7 @@ namespace bx
 {
 	inline int64_t getHPCounter()
 	{
-#if BX_PLATFORM_WINDOWS || BX_PLATFORM_XBOX360
+#if BX_PLATFORM_WINDOWS || BX_PLATFORM_XBOX360 || BX_PLATFORM_WINRT
 		LARGE_INTEGER li;
 		// Performance counter value may unexpectedly leap forward
 		// http://support.microsoft.com/kb/274323
@@ -44,7 +44,7 @@ namespace bx
 
 	inline int64_t getHPFrequency()
 	{
-#if BX_PLATFORM_WINDOWS || BX_PLATFORM_XBOX360
+#if BX_PLATFORM_WINDOWS || BX_PLATFORM_XBOX360 || BX_PLATFORM_WINRT
 		LARGE_INTEGER li;
 		QueryPerformanceFrequency(&li);
 		return li.QuadPart;
diff --git a/include/bx/uint32_t.h b/include/bx/uint32_t.h
index f4a65b4..7bacfc5 100644
--- a/include/bx/uint32_t.h
+++ b/include/bx/uint32_t.h
@@ -29,7 +29,7 @@
 #include "bx.h"
 
 #if BX_COMPILER_MSVC
-#	if BX_PLATFORM_WINDOWS
+#	if BX_PLATFORM_WINDOWS || BX_PLATFORM_WINRT
 #		include <math.h> // math.h is included because VS bitches:
 						 // warning C4985: 'ceil': attributes not present on previous declaration.
 						 // must be included before intrin.h.