Fiber-wireless (FiWi) access networks comprising wireless local area networks (WLANs) and passive optical networks (PONs) have attracted much attention recently for future cyber-physical systems (CPSs). Because of the explosive growth of smart devices such as smart phones and sensors, the number of such devices has also grown phenomenally that require real time communication demanding quality of service (QoS)-centric applications for CPSs, such as smart grid, medical, and traffic control systems, which construct smart society. To deal with such situations, the FiWi access networks may be a suitable choice since they are capable of providing both wide bandwidth and flexibility. However, combining the WLAN and PON in FiWithat are inherently different networking technologies leads to inefficient data transmission in the point of junction of the WLAN and PON. Therefore, the QoS of real time communication degrades significantly. In this paper, we address this problem involving QoS degradation in theFiWi networks, and propose a QoS control scheme, which is based on cooperation between the WLAN and PON. Through computer-based simulations, we demonstrate that our proposedscheme can significantly improve the QoS performance of the FiWi access networks for CPSs.