diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index c9e3a16c4..420bbfab2 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -127,8 +127,9 @@ jobs:
         os: [Windows]
         python:
           - 3.6
-          - 3.7
-          - 3.8
+          # Commented out, since Windows tests are expensively slow.
+          # - 3.7
+          # - 3.8
           - 3.9
         group: [1, 2]