diff --git a/Makefile b/Makefile
index 469a486b..68f6e57c 100644
--- a/Makefile
+++ b/Makefile
@@ -17,7 +17,7 @@ USER_REPO ?= $(shell git remote get-url origin | sed -e 's/.*\/\([^/]*\)\/\([^/]
 BRANCH ?= $(shell git rev-parse --abbrev-ref HEAD  2>/dev/null || git describe --tags --abbrev=0  2>/dev/null )
 empty:=
 space:= $(empty) $(empty)
-DOCKER_PROJECT ?= $(shell echo $(subst $(space),,$(USER_REPO)_$(BRANCH)) | tr -c -s '[:alnum:][=-=]' '_')
+DOCKER_PROJECT ?= $(shell echo $(subst $(space),,$(USER_REPO)_$(BRANCH)) | tr -c -s '[:alnum:][=-=]' '_' | tr '[:upper:]' '[:lower:]')
 DOCKER_COMPOSE_COMMANDS_SUPPORTED := up down config
 DEFAULT_DOCKER_COMPOSE_COMMAND  := up
 GRPC_MTLS_CERT_FILES_EXISTS = 0