diff --git a/simgear/math/SGMisc.hxx b/simgear/math/SGMisc.hxx
index cd448b05..a295ac3f 100644
--- a/simgear/math/SGMisc.hxx
+++ b/simgear/math/SGMisc.hxx
@@ -18,6 +18,8 @@
 #ifndef SGMisc_H
 #define SGMisc_H
 
+#include <cmath>
+
 template<typename T>
 class SGMisc {
 public: