diff --git a/simgear/misc/strutils.cxx b/simgear/misc/strutils.cxx
index aee6a49c..27fae3df 100644
--- a/simgear/misc/strutils.cxx
+++ b/simgear/misc/strutils.cxx
@@ -30,6 +30,7 @@
 #include <cctype>
 #include <cerrno>
 #include <codecvt>
+#include <locale>
  
 #include "strutils.hxx"