diff --git a/src/sfizz.hpp b/src/sfizz.hpp
index 9c9d9208..b2203b6b 100644
--- a/src/sfizz.hpp
+++ b/src/sfizz.hpp
@@ -9,6 +9,7 @@
   @brief sfizz public C++ API
 */
 
+#pragma once
 #include <string>
 #include <utility>
 #include <vector>