diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index e260277..a5da2e9 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -9,7 +9,7 @@ on:
 
 jobs:
   build:
-    runs-on: ubuntu-18.04
+    runs-on: ubuntu-20.04
     steps:
       - name: Set Stan Version
         id: scala_stan_version