diff --git a/benchmarks/iozone/Makefile b/benchmarks/iozone/Makefile
index 25c77e99d604..146c7004f769 100644
--- a/benchmarks/iozone/Makefile
+++ b/benchmarks/iozone/Makefile
@@ -27,10 +27,12 @@ ALL_TARGET=
 MAN1=		iozone.1
 PLIST_FILES=	bin/iozone
 
-OPTIONS=	THREADS "Enable threading (uses pthreads)"	on
-
 .include <bsd.port.pre.mk>
 
+.if ${OSVERSION} > 500000
+OPTIONS=	THREADS "Enable threading (uses pthreads)"	on
+.endif
+
 .if defined (WITH_THREADS)
 CFLAGS+=	-pthread
 MAKE_ENV=	LDFLAGS=-lpthread