diff --git a/Dockerfile b/Dockerfile
index 65c5e681..914d06a9 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -17,10 +17,11 @@ FROM python:3-alpine
 
 WORKDIR /app
 
-RUN adduser radicale --home /var/lib/radicale --system --uid 1000 --disabled-password \
+RUN addgroup -g 1000 radicale \
+    && adduser radicale --home /var/lib/radicale --system --uid 1000 --disabled-password -G radicale \
     && apk add --no-cache ca-certificates openssl
 
-COPY --chown=radicale --from=builder /app/venv /app
+COPY --chown=radicale:radicale --from=builder /app/venv /app
 
 # Persistent storage for data
 VOLUME /var/lib/radicale
diff --git a/Dockerfile.dev b/Dockerfile.dev
index b2d996ce..36ff98e5 100644
--- a/Dockerfile.dev
+++ b/Dockerfile.dev
@@ -15,10 +15,11 @@ FROM python:3-alpine
 
 WORKDIR /app
 
-RUN adduser radicale --home /var/lib/radicale --system --uid 1000 --disabled-password \
+RUN addgroup -g 1000 radicale \
+    && adduser radicale --home /var/lib/radicale --system --uid 1000 --disabled-password -G radicale \
     && apk add --no-cache ca-certificates openssl
 
-COPY --chown=radicale --from=builder /app/venv /app
+COPY --chown=radicale:radicale --from=builder /app/venv /app
 
 # Persistent storage for data
 VOLUME /var/lib/radicale
@@ -28,4 +29,4 @@ EXPOSE 5232
 ENTRYPOINT [ "/app/bin/python", "/app/bin/radicale"]
 CMD ["--hosts", "0.0.0.0:5232"]
 
-USER radicale
\ No newline at end of file
+USER radicale