diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index 8ad846a84580a397c4b451643c401b80e5d2e438..9ef5b60b50c4ffdce5f85529e3ef80f3ce7ea3ba 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -39,6 +39,9 @@ jobs:
 
     - name: "Install ZKAPAuthorizer and dependencies"
       run: |
+        # Get a Python 2 compatible version of setuptools_scm so that pip
+        # doesn't install a Python 2 incompatible version for cbor2.
+        pip install setuptools_scm==1.17.0
         python -m pip install -v ./[test]
 
     - name: "Dump Python Environment"