diff --git a/sphinx/Dockerfile b/sphinx/Dockerfile
index 67cab60..5267299 100644
--- a/sphinx/Dockerfile
+++ b/sphinx/Dockerfile
@@ -1,18 +1,19 @@
 ARG REGISTRY=swh-jenkins
 FROM $REGISTRY/base
 
 USER root
 RUN DEBIAN_FRONTEND=noninteractive apt-get update && \
   apt-get install -y --no-install-recommends \
     python3-sphinx \
     sphinx-rtd-theme-common \
     graphviz \
     python3-sphinxcontrib.httpdomain \
     python3-recommonmark \
     libffi-dev \
     inkscape \
+	dia \
 	myrepos \
 	make && \
   rm -rf /var/lib/apt/lists/*
 
 USER jenkins