diff --git a/Lib/test/test_regrtest.py b/Lib/test/test_regrtest.py
index 02f6e0c74b5ce8..874c6bb76b1afe 100644
--- a/Lib/test/test_regrtest.py
+++ b/Lib/test/test_regrtest.py
@@ -2283,7 +2283,8 @@ def test_python_opts(self):
         proc = subprocess.run(cmd,
                               stdout=subprocess.PIPE,
                               stderr=subprocess.STDOUT,
-                              text=True)
+                              text=True,
+                              env=support.make_clean_env())
         self.assertEqual(proc.returncode, 0, proc)
 
     def test_add_python_opts(self):