diff --git a/Arduino_Threads.h b/Arduino_Threads.h
index 6d313cc..704184e 100644
--- a/Arduino_Threads.h
+++ b/Arduino_Threads.h
@@ -1,3 +1,6 @@
+#ifndef ARDUINO_THREADS_H_
+#define ARDUINO_THREADS_H_
+
 #include <MemoryPool.h>
 
 
@@ -141,4 +144,6 @@ private: \
 CONCAT(tabname,Class) tabname;
 
 #include "Wire.h"
-#include "SerialDispatcher.h"
\ No newline at end of file
+#include "SerialDispatcher.h"
+
+#endif /* ARDUINO_THREADS_H_ */