diff --git a/.github/workflows/build-and-push-docker-base-image.yml b/.github/workflows/build-and-push-docker-base-image.yml
index 77aea8d..7a74bba 100644
--- a/.github/workflows/build-and-push-docker-base-image.yml
+++ b/.github/workflows/build-and-push-docker-base-image.yml
@@ -40,5 +40,5 @@ jobs:
           build-args: ALPINE_VERSION=${{ env.ALPINE_VERSION }}
           push: true
           tags: |
-            ghcr.io/${{ github.repository_owner }}/planka:base-latest
-            ghcr.io/${{ github.repository_owner }}/planka:base-${{ env.ALPINE_VERSION }}
+            ghcr.io/${{ lowercase(github.repository_owner) }}/planka:base-latest
+            ghcr.io/${{ lowercase(github.repository_owner) }}/planka:base-${{ env.ALPINE_VERSION }}