diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 8c0191cd62..9d93f0d2ad 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -71,7 +71,7 @@ jobs:
       - name: install dependencies
         run: |
           sudo /usr/bin/python -m pip install -U pip
-          sudo /usr/bin/python -m pip install xmlschema numpy
+          sudo /usr/bin/python -m pip install xmlschema numpy lxml
           sudo /usr/bin/python -m pip install src/bcf
 
       - name: Test