diff --git a/ci/install.sh b/ci/install.sh
index 08e3d24e..71daa32a 100644
--- a/ci/install.sh
+++ b/ci/install.sh
@@ -11,6 +11,7 @@ main() {
     curl -LSfs https://japaric.github.io/trust/install.sh | \
         sh -s -- --git rust-lang/mdbook --tag $tag
 
+    pip install python-dateutil --user
     pip install linkchecker --user
 }