Compared with internal combustion engines, fuel cell technology can effectively reduce greenhouse gas emissions to achieve the goal of carbon neutral. Especially, polyelectrolyte fuel cells, divided into proton exchange membrane fuel cells and anion exchange membrane fuel cells, are widely used in the field of new energy vehicles and energy transfer systems. As a transition, ion exchange membrane is one of the important components in fuel cells, always promotes ion (H+ or OH−) transport, isolates the reaction gas (H2 and O2), and prevents electronic transmission between cathode and anode. This chapter mainly discusses the development and latest advancement of ion exchange membranes in polyelectrolyte fuel cells, including proton exchange membranes and anion exchange membranes. In the first half, some main structures of proton exchange membranes (containing perfluorosulfonic acid polymer membranes, fluoropolymer membranes, nonfluorinated polymer membranes, and composite membranes) are introduced. Meanwhile, in the latter half, materials and advancement for anion exchange groups as well as polymer backbones in anion exchange membranes are presented in detail. Furthermore, novel polymer fabrication methods (e.g., superacid-catalyzed polymerizations) and materials (e.g., ether-free backbone-based polymers) are highlighted for the improvement of low production cost and chemical stability. However, although ion exchange membranes have made great progress in reducing production costs and improving chemical properties after decades of development, other properties of the membranes need to be improved such as compatibility with other components in fuel cells.