Fog computing is considered as a trend for future wireless sensor networks (WSNs) due to low latency and energy-saving. However, because different fog services have different quality of service (QoS) requirements and related data are forwarded by content-aware traffic control, it is a must for fog computing advanced WSNs to deploy QoS policy dynamically. Software-Defined Networking (SDN) is a future network technique that makes the underlying networks programmable dynamically. In this paper, we propose a software-defined QoS provisioning mechanism for fog computing advanced WSNs. To our best knowledge, this paper is the first to realize software defined QoS provisioning for WSNs.