diff --git a/js/src/js.c b/js/src/js.c
index 5cdc809c9a86..eec245c50a57 100644
--- a/js/src/js.c
+++ b/js/src/js.c
@@ -46,6 +46,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <locale.h>
 #include "jstypes.h"
 #include "jsarena.h"
 #include "jsutil.h"
@@ -2502,6 +2503,8 @@ main(int argc, char **argv, char **envp)
 
     gStackBase = (jsuword)&stackDummy;
 
+    setlocale(LC_ALL, "");
+
 #ifdef XP_OS2
    /* these streams are normally line buffered on OS/2 and need a \n, *
     * so we need to unbuffer then to get a reasonable prompt          */