In this chapter, we will discuss the increasing applications of MXenes in membrane-based water treatment processes. The commonly used processes will be discussed as there are different types of filtrations. The MXenes-based membranes' separation mechanisms, preparation methods, and applications in water treatment are covered. The main concept of each process is clarified and the related studies are discussed. However, basic information on the types of MXenes, particle preparation methods, and development timelines can be found elsewhere.