diff --git a/source/include/Kyty/Sys/MacOS/SysMacOSSync.h b/source/include/Kyty/Sys/MacOS/SysMacOSSync.h
new file mode 100644
index 0000000..2e6fc70
--- /dev/null
+++ b/source/include/Kyty/Sys/MacOS/SysMacOSSync.h
@@ -0,0 +1,84 @@
+#ifndef SYS_MACOS_INCLUDE_KYTY_SYSSYNC_H_
+#define SYS_MACOS_INCLUDE_KYTY_SYSSYNC_H_
+
+// IWYU pragma: private
+
+#if KYTY_PLATFORM != KYTY_PLATFORM_MACOS
+//#error "KYTY_PLATFORM != KYTY_PLATFORM_MACOS"
+#else
+
+#include <pthread.h>
+#include <unistd.h>
+
+namespace Kyty {
+
+class SysCS
+{
+public:
+	SysCS() = default;
+
+	void Init()
+	{
+		EXIT_IF(m_check_ptr != nullptr);
+
+		m_check_ptr = this;
+
+		pthread_mutexattr_t attr {};
+		pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE_NP);
+		pthread_mutex_init(&m_mutex, &attr);
+		pthread_mutexattr_destroy(&attr);
+	}
+
+	void Delete()
+	{
+		EXIT_IF(m_check_ptr != this);
+
+		m_check_ptr = nullptr;
+		pthread_mutex_destroy(&m_mutex);
+	}
+
+	~SysCS() { EXIT_IF(m_check_ptr != nullptr); }
+
+	void Enter()
+	{
+		EXIT_IF(m_check_ptr != this);
+
+		pthread_mutex_lock(&m_mutex);
+	}
+
+	bool TryEnter()
+	{
+		EXIT_IF(m_check_ptr != this);
+
+		return pthread_mutex_trylock(&m_mutex) == 0;
+	}
+
+	void Leave()
+	{
+		EXIT_IF(m_check_ptr != this);
+
+		pthread_mutex_unlock(&m_mutex);
+	}
+
+	KYTY_CLASS_NO_COPY(SysCS);
+
+private:
+	SysCS*          m_check_ptr = nullptr;
+	pthread_mutex_t m_mutex {};
+};
+
+inline void sys_sleep(uint32_t ms)
+{
+	struct timespec ts
+	{
+	};
+	ts.tv_sec  = ms / 1000;
+	ts.tv_nsec = static_cast<int64_t>(ms % 1000) * 1000000;
+	nanosleep(&ts, nullptr);
+}
+
+} // namespace Kyty
+
+#endif
+
+#endif /* SYS_MACOS_INCLUDE_KYTY_SYSSYNC_H_ */