diff --git a/util/docker/docs.coreboot.org/Dockerfile b/util/docker/docs.coreboot.org/Dockerfile
index a475b8cb12..27966ac80d 100644
--- a/util/docker/docs.coreboot.org/Dockerfile
+++ b/util/docker/docs.coreboot.org/Dockerfile
@@ -1,5 +1,5 @@
 FROM debian:stable
-RUN apt-get update && apt-get install -y make python-sphinx python-recommonmark python-sphinx-rtd-theme
+RUN apt-get update && apt-get install -y make python-sphinx python-recommonmark python-sphinx-rtd-theme && apt-get clean
 USER nobody
 VOLUME /data-in /data-out
 ENTRYPOINT bash -c "cd /data-in/Documentation && make sphinx BUILDDIR=/tmp/build && rm -rf /data-out/* && mv /tmp/build/html/* /data-out/"