diff --git a/Makefile b/Makefile
index ff8edc0..3864d60 100644
--- a/Makefile
+++ b/Makefile
@@ -194,7 +194,7 @@ pseudoxml:
 install: vendor
 
 composer.phar:
-	docker/install-composer.sh
+	chmod +x docker/install-composer.sh && docker/install-composer.sh
 
 vendor: composer.phar
 	php composer.phar install