diff --git a/tools/run_tests/performance/run_worker_python.sh b/tools/run_tests/performance/run_worker_python.sh
index cd7d0ebbae4..01241c8296a 100755
--- a/tools/run_tests/performance/run_worker_python.sh
+++ b/tools/run_tests/performance/run_worker_python.sh
@@ -15,6 +15,6 @@
 
 set -ex
 
-cd $(dirname $0)/../../..
+cd "$(dirname "$0")/../../.."
 
-PYTHONPATH=src/python/grpcio_tests:src/python/gens py27/bin/python src/python/grpcio_tests/tests/qps/qps_worker.py $@
+PYTHONPATH=src/python/grpcio_tests:src/python/gens py27/bin/python src/python/grpcio_tests/tests/qps/qps_worker.py "$@"