diff --git a/math/jakarta-commons-math/Makefile b/math/jakarta-commons-math/Makefile
index e8339a4457c6..178019d6bf65 100644
--- a/math/jakarta-commons-math/Makefile
+++ b/math/jakarta-commons-math/Makefile
@@ -33,6 +33,8 @@ PLIST_FILES+=	%%JAVAJARDIR%%/${DESTJARFILE}
 
 OPTIONS_DEFINE=	DOCS
 
+MAKE_ENV=	LANG=en_US.ISO8859-1
+
 .include <bsd.port.options.mk>
 
 .if ${PORT_OPTIONS:MDOCS}