diff --git a/sbin/spark-config.sh b/sbin/spark-config.sh
index a7a44cdde6c7..b7284487c511 100755
--- a/sbin/spark-config.sh
+++ b/sbin/spark-config.sh
@@ -26,5 +26,8 @@ fi
 
 export SPARK_CONF_DIR="${SPARK_CONF_DIR:-"${SPARK_HOME}/conf"}"
 # Add the PySpark classes to the PYTHONPATH:
-export PYTHONPATH="${SPARK_HOME}/python:${PYTHONPATH}"
-export PYTHONPATH="${SPARK_HOME}/python/lib/py4j-0.10.3-src.zip:${PYTHONPATH}"
+if [ -z "${PYSPARK_PYTHONPATH_SET}" ]; then
+  export PYTHONPATH="${SPARK_HOME}/python:${PYTHONPATH}"
+  export PYTHONPATH="${SPARK_HOME}/python/lib/py4j-0.10.3-src.zip:${PYTHONPATH}"
+  export PYSPARK_PYTHONPATH_SET=1
+fi