diff --git a/tools/run_tests/helper_scripts/run_tests_in_workspace.sh b/tools/run_tests/helper_scripts/run_tests_in_workspace.sh
index 7cff51fd673..37ac0af6aec 100755
--- a/tools/run_tests/helper_scripts/run_tests_in_workspace.sh
+++ b/tools/run_tests/helper_scripts/run_tests_in_workspace.sh
@@ -31,6 +31,4 @@ git submodule foreach 'cd "${repo_root}/${WORKSPACE_NAME}" \
     && git submodule update --init --reference ${repo_root}/${name} ${name}'
 
 echo "Running run_tests.py in workspace ${WORKSPACE_NAME}"
-# TODO(jtattermusch): switch to python3 as soon as it stops breaking Python MacOS tests.
-# See #28125.
-python "${WORKSPACE_NAME}/tools/run_tests/run_tests.py" "$@"
+python3 "${WORKSPACE_NAME}/tools/run_tests/run_tests.py" "$@"