diff --git a/contrib/subtree/Makefile b/contrib/subtree/Makefile
index 05cdd5c9b2f..36ae3e4f0a9 100644
--- a/contrib/subtree/Makefile
+++ b/contrib/subtree/Makefile
@@ -30,12 +30,12 @@ $(GIT_SUBTREE): $(GIT_SUBTREE_SH)
 doc: $(GIT_SUBTREE_DOC)
 
 install: $(GIT_SUBTREE)
-	$(INSTALL) -m 755 $(GIT_SUBTREE) $(libexecdir)
+	$(INSTALL) -m 755 $(GIT_SUBTREE) $(DESTDIR)$(libexecdir)
 
 install-doc: install-man
 
 install-man: $(GIT_SUBTREE_DOC)
-	$(INSTALL) -m 644 $^ $(man1dir)
+	$(INSTALL) -m 644 $^ $(DESTDIR)$(man1dir)
 
 $(GIT_SUBTREE_DOC): $(GIT_SUBTREE_XML)
 	xmlto -m $(MANPAGE_NORMAL_XSL)  man $^