diff --git a/src/python/oftest/dataplane.py b/src/python/oftest/dataplane.py
index 76aff75..056f22a 100644
--- a/src/python/oftest/dataplane.py
+++ b/src/python/oftest/dataplane.py
@@ -496,7 +496,9 @@
         """
         for port_number in self.port_list.keys():
             self.port_list[port_number].kill()
-            if join_threads:
+
+        if join_threads:
+            for port_number in self.port_list.keys():
                 self.logger.debug("Joining " + str(port_number))
                 self.port_list[port_number].join()