diff --git a/.gitea/workflows/docker-build.yml b/.gitea/workflows/docker-build.yml
index e2d168f..2847d01 100644
--- a/.gitea/workflows/docker-build.yml
+++ b/.gitea/workflows/docker-build.yml
@@ -25,6 +25,13 @@ jobs:
           password: ${{ secrets.REGISTRY_TOKEN }}
 
       - name: Build and Push
+        env:
+          # This Dockerfile uses BuildKit features (`# syntax=docker/dockerfile:1.7`
+          # and `RUN --mount=type=cache`). Without this the CLI falls back to the
+          # legacy builder, which ignores the syntax directive and fails at the first
+          # `--mount`. DOCKER_BUILDKIT=1 activates dockerd's integrated BuildKit
+          # backend (no separate buildx plugin required).
+          DOCKER_BUILDKIT: "1"
         run: |
           IMAGE="registry.alwisp.com/${{ gitea.repository }}"
           GIT_SHA="$(git rev-parse --short HEAD)"