diff --git a/src/core/model/nstime.h b/src/core/model/nstime.h
index 1af8b4485..af37f9754 100644
--- a/src/core/model/nstime.h
+++ b/src/core/model/nstime.h
@@ -27,7 +27,6 @@
 #include "unused.h"
 #include <stdint.h>
 #include <limits>
-#include <cmath>
 #include <ostream>
 #include <set>