diff --git a/aos/common/mutex.h b/aos/common/mutex.h
new file mode 100644
index 0000000..c1d6f95
--- /dev/null
+++ b/aos/common/mutex.h
@@ -0,0 +1,70 @@
+#ifndef AOS_COMMON_MUTEX_H_
+#define AOS_COMMON_MUTEX_H_
+
+#ifdef __VXWORKS__
+#include <semLib.h>
+#endif
+
+#include "aos/aos_core.h"
+#include "aos/common/macros.h"
+#include "aos/common/type_traits.h"
+
+namespace aos {
+
+// An abstraction of a mutex that has implementations both for the
+// atom and for the cRIO.
+// If there are multiple tasks or processes contending for the mutex,
+// higher priority ones will succeed in locking first,
+// and tasks of equal priorities have the same chance of getting the lock.
+// There is no priority inversion protection.
+class Mutex {
+ public:
+  // Creates an unlocked mutex.
+  Mutex();
+#ifdef __VXWORKS__
+  // Will not make sure that it is either locked or unlocked.
+  ~Mutex();
+#endif
+  // Locks the mutex. If it fails, it calls LOG(FATAL).
+  void Lock();
+  // Unlocks the mutex. Fails like Lock.
+  // Multiple unlocking might be considered failure.
+  void Unlock();
+  // Locks the mutex unless it is already locked.
+  // Returns whether it succeeded or not.
+  // Doesn't wait for the mutex to be unlocked if it is locked.
+  bool TryLock();
+
+ private:
+#ifdef __VXWORKS__
+  typedef SEM_ID ImplementationType;
+#else
+  typedef mutex ImplementationType;
+#endif
+  ImplementationType impl_;
+#ifdef __VXWORKS__
+  DISALLOW_COPY_AND_ASSIGN(Mutex);
+#endif
+};
+
+// A class that locks a Mutex when constructed and unlocks it when destructed.
+// Designed to be used as a local variable so that
+// the mutex will be unlocked when the scope is exited.
+// Should it fail for some reason, it dies with LOG(FATAL).
+class MutexLocker {
+ public:
+  explicit MutexLocker(Mutex *mutex) : mutex_(mutex) {
+    mutex_->Lock();
+  }
+  ~MutexLocker() {
+    mutex_->Unlock();
+  }
+
+ private:
+  Mutex *mutex_;
+  DISALLOW_COPY_AND_ASSIGN(MutexLocker);
+};
+
+}  // namespace aos
+
+#endif  // AOS_COMMON_MUTEX_H_