diff --git a/.test-conda-env-py3.yml b/.test-conda-env-py3.yml
index 6459d4c06fcff2b84c489e7f64395cffe86f309f..8122333f3131191cbaded479c0ff068bb8515d33 100644
--- a/.test-conda-env-py3.yml
+++ b/.test-conda-env-py3.yml
@@ -12,3 +12,4 @@ dependencies:
 - islpy
 - sphinx-autodoc-typehints
 - mpi4py
+- openmpi  # Force using Open MPI since our pytest infrastructure needs it