diff --git a/Makefile b/Makefile
index cff149ae..6c514454 100644
--- a/Makefile
+++ b/Makefile
@@ -1,4 +1,5 @@
-INSTALLDIR := /usr/share/libretro/shaders/shaders_slang
+PREFIX := /usr
+INSTALLDIR := $(PREFIX)/share/libretro/shaders/shaders_slang
 
 all:
 	@echo "Nothing to make for slang-shaders."