diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index bc63b06..8897a64 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -11,6 +11,7 @@ jobs:
     strategy:
       matrix:
         os:
+          - macos-10.15
           - ubuntu-18.04
         ghc:
           - 8.8.4