diff --git a/webtrees/Dockerfile b/webtrees/Dockerfile
index 7a11a6571..3fdbc949a 100644
--- a/webtrees/Dockerfile
+++ b/webtrees/Dockerfile
@@ -16,6 +16,7 @@ RUN \
     && apt-get install -y \
     jq \
     curl \
+    yamllint \
     && apt-get clean \
     \
     ##################