diff --git a/Makefile b/Makefile
index d12505e..7872bff 100644
--- a/Makefile
+++ b/Makefile
@@ -76,7 +76,7 @@ endif
 endif
 
 ## Ensures NPM dependencies are installed without having to run this all the time.
-webapp/node_modules: webapp/package.json
+webapp/node_modules: $(wildcard webapp/package.json)
 ifneq ($(HAS_WEBAPP),)
 	cd webapp && $(NPM) install
 	touch $@