diff --git a/webui/Dockerfile b/webui/Dockerfile
index 5102a3969..c78d2bfd1 100644
--- a/webui/Dockerfile
+++ b/webui/Dockerfile
@@ -7,7 +7,8 @@ RUN apt-get -yq update \
 && apt-get -yq --no-install-suggests --no-install-recommends --force-yes install apt-transport-https \
 && curl -sS https://dl.yarnpkg.com/debian/pubkey.gpg | apt-key add - \
 && echo "deb https://dl.yarnpkg.com/debian/ stable main" |  tee /etc/apt/sources.list.d/yarn.list \
-&& apt-get -yq update && apt-get -yq --no-install-suggests --no-install-recommends --force-yes install yarn
+&& apt-get -yq update && apt-get -yq --no-install-suggests --no-install-recommends --force-yes install yarn \
+&& rm -fr /var/lib/apt/lists/
 
 COPY package.json $WEBUI_DIR/
 COPY yarn.lock $WEBUI_DIR/