diff --git a/libs/evoral/evoral/Note.hpp b/libs/evoral/evoral/Note.hpp
index 88d4077af9..dbecb7dd6e 100644
--- a/libs/evoral/evoral/Note.hpp
+++ b/libs/evoral/evoral/Note.hpp
@@ -20,6 +20,7 @@
 #define EVORAL_NOTE_HPP
 
 #include <algorithm>
+#include <assert.h>
 #include <glib.h>
 #include <stdint.h>