diff --git a/tinyexpr.h b/tinyexpr.h
index 8278633..324bb93 100644
--- a/tinyexpr.h
+++ b/tinyexpr.h
@@ -22,8 +22,8 @@
  * 3. This notice may not be removed or altered from any source distribution.
  */
 
-#ifndef __TINYEXPR_H__
-#define __TINYEXPR_H__
+#ifndef TINYEXPR_H
+#define TINYEXPR_H
 
 
 #ifdef __cplusplus