As mobile communication systems continuously advance to meet the evolving needs of end users, several intermediary technologies have emerged, laying the groundwork for the futuristic wireless standards. This chapter presents an extensive review of multiple access techniques designed for the next-generation wireless communication systems. The review begins with an analysis of orthogonal multiple access (OMA) schemes, including frequency division multiple access (FDMA), time division multiple access (TDMA), code division multiple access (CDMA), and orthogonal frequency division multiple access (OFDMA), which have been deployed in 1G, 2G, 3G, and 4G networks, respectively. A general comparison of communication systems from 1G through 5G is also provided. Furthermore, the chapter explores 5G wireless technologies that incorporate non-orthogonal multiple access (NOMA) methods and discusses uplink NOMA and downlink NOMA approaches along with power-domain NOMA (PD-NOMA) and code-domain NOMA (CD-NOMA) schemes. Additionally, the chapter also discusses a generic multiple access technique called rate splitting multiple access (RSMA), which is being considered for future generations of mobile systems. Finally, the chapter discusses the carrier sense multiple access protocol with collision avoidance (CSMA/CA) random access protocol, which are extensively used in ad-hoc networks and its variants in detail.