diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 4e69beadbe991abec364378ee0df83be5e69da23..241c74686e52c510b237b11f52c5343f962a8852 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -100,6 +100,8 @@ jobs:
                 curl -L -O -k https://gitlab.tiker.net/inducer/ci-support/raw/master/ci-support.sh
                 . ./ci-support.sh
                 build_py_project_in_conda_env
+
+                export CISUPPORT_PARALLEL_PYTEST=no
                 test_py_project
 
 # vim: sw=4