diff --git a/Makefile b/Makefile
index 623aaf7..31f9aaa 100644
--- a/Makefile
+++ b/Makefile
@@ -1,6 +1,6 @@
 .POSIX:
 
-PREFIX = /usr/local
+PREFIX ?= /usr/local
 MANPREFIX = $(PREFIX)/share/man
 
 install: