This chapter identifies the leading researchers and their contribution in the design of wireless medium access control (MAC) protocols. It reviews some representative wireless MAC protocols. The chapter discusses the issues and challenges in the design of wireless MAC protocols. It describes commonly used network performance metrics. The chapter analyses the impact of radio propagation on MAC protocol design. It shows that the effect of network performance on MAC protocol design. A good MAC protocol for Wireless local area networks should provide an efficient mechanism for sharing a limited wireless channel bandwidth, together with simplicity of operation, high bandwidth utilization, and fairness in serving all stations. MAC protocols designed for wireless ad hoc networks are quite different from those designed for infrastructure-based networks. In addition to the wireless MAC protocol classification, the existing MAC protocols can be divided into two main categories: contention based and contention-free.