Over the last few decades, the effectiveness of the conventional water treatment processes has become limited due to its failure to meet stringent water quality regulations, the emergence of non-conventional contaminants, and space limitations. Membrane technology can serve as a viable option to meet the limitations of the conventional treatment processes due to low chemical use, higher efficiency, easy operation, smaller footprint, and better quality treatment. But its effective usage is hindered due to fouling, shorter life span, and selectivity–permeability trade-off. Thus, there is a need for new-generation membranes that can surpass the limitations of the conventional membrane technologies, with less or no decrement in the efficiency of the treatment. With the advancements in material sciences and membrane fabrication processes, it could be possible to overcome the problems of conventional membrane treatment processes. In this chapter, a brief introduction of the membrane technology, its advantages over conventional treatment processes, commonly used pressure-driven membranes and membrane fabrication processes, the problems of conventional membranes, and some of the promising new-generation membrane materials and membrane systems, and water and wastewater treatment have been discussed.