diff --git a/.github/workflows/sphinx.yml b/.github/workflows/sphinx.yml
index 91e0f7dc..c0cf6e18 100644
--- a/.github/workflows/sphinx.yml
+++ b/.github/workflows/sphinx.yml
@@ -30,6 +30,8 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
+      - name: Install Gnuplot
+        run: sudo apt -y install gnuplot
       - name: Install Sphinx
         run: sudo pip install sphinx
       - name: Install Sphinx RTD Theme