The Internet of Things (IoT) is a key enabler of smart cities, where a variety of applications proliferate to help citizen services. As different IoT applications have different service holders, it becomes necessary to employ network slicing (NS) to gain distinct virtual networks, and differentiated quality of service (QoS) guarantees. Other than conventional IoT scenarios, smart city IoT relies on 6G networks for broad coverage, ultra-low latency, and reliable connection. This chapter proposes a selforganizing network (SON) driven network slicing architecture, where software-defined networking (SDN) and network function virtualization (NFV) also play important roles. Some preliminary simulation results are given to validate the efficiency of our design.