diff --git a/.evergreen/config.yml b/.evergreen/config.yml
index c161aeaa21..5e2ce14d3a 100644
--- a/.evergreen/config.yml
+++ b/.evergreen/config.yml
@@ -1568,7 +1568,7 @@ axes:
         variables:
           skip_EC2_auth_test: true
           skip_ECS_auth_test: true
-          python3_binary: python3
+          python3_binary: /Library/Frameworks/Python.framework/Versions/3.8/bin/python3
           libmongocrypt_url: https://s3.amazonaws.com/mciuploads/libmongocrypt/macos/master/latest/libmongocrypt.tar.gz
       - id: rhel62
         display_name: "RHEL 6.2 (x86_64)"
diff --git a/.evergreen/run-mongodb-aws-test.sh b/.evergreen/run-mongodb-aws-test.sh
index f0d59e960a..e276a82bb4 100755
--- a/.evergreen/run-mongodb-aws-test.sh
+++ b/.evergreen/run-mongodb-aws-test.sh
@@ -39,7 +39,12 @@ fi
 # show test output
 set -x
 
-VIRTUALENV=$(command -v virtualenv)
+# Workaround macOS python 3.9 incompatibility with system virtualenv.
+if [ $(uname -s) = "Darwin" ]; then
+    VIRTUALENV="/Library/Frameworks/Python.framework/Versions/3.9/bin/python3 -m virtualenv"
+else
+    VIRTUALENV=$(command -v virtualenv)
+fi
 
 authtest () {
     if [ "Windows_NT" = "$OS" ]; then