diff --git a/usr.bin/ctags/fortran.c b/usr.bin/ctags/fortran.c
index 05b4acbf72f3..2195606242c4 100644
--- a/usr.bin/ctags/fortran.c
+++ b/usr.bin/ctags/fortran.c
@@ -43,6 +43,7 @@ __FBSDID("$FreeBSD$");
 #include <ctype.h>
 #include <limits.h>
 #include <stdio.h>
+#include <string.h>
 
 #include "ctags.h"