diff --git a/gettext.h b/gettext.h
index 8192e2e..e499680 100644
--- a/gettext.h
+++ b/gettext.h
@@ -26,6 +26,7 @@
 #if ENABLE_NLS
 
 /* Get declarations of GNU message catalog functions.  */
+# include <locale.h>
 # include <libintl.h>
 
 /* You can set the DEFAULT_TEXT_DOMAIN macro to specify the domain used by