diff --git a/Makefile b/Makefile
index 481a95c..43452bb 100644
--- a/Makefile
+++ b/Makefile
@@ -53,6 +53,9 @@ ifndef GITHUB_USERNAME
 endif
 ifneq "$(shell git branch --show-current)" "master"
 	$(error This command can only be run on the master branch)
+endif
+ifneq "$(shell git diff --name-only master)" ""
+	$(error There are uncommitted changes in the working directory)
 endif
 	echo $$GITHUB_PAT | docker login ghcr.io --username $$GITHUB_USERNAME --password-stdin
 	VERSION=$(VERSION) $(COMPOSE_PUBLISH) build