diff --git a/Jamrules.common b/Jamrules.common
index 7ad058b049..0f0e5b6db3 100644
--- a/Jamrules.common
+++ b/Jamrules.common
@@ -29,6 +29,7 @@
 # OS specifics
 #
 if $(NT) {
+  SLASH = \\ ;
 	POSIXSHELL = sh ;
 	NULLDEV = NUL ;
 	CAT = type ;