<p>Rechargeable zinc-air batteries (RZABs) are considered among the most promising energy storage systems because they offer high energy density, are environmentally benign, and are less costly to produce. Rechargeable zinc-air batteries require bifunctional electrocatalysts capable of efficiently catalyzing both the oxygen reduction reaction (ORR) during discharge and the oxygen evolution reaction (OER) during charging. However, their practical application is severely hindered by sluggish ORR and OER kinetics at the air cathode, resulting in reduced energy efficiency and shortened cycle life. Density Functional Theory (DFT) has become an important tool for understanding how these reactions occur and for designing better catalysts to improve performance. This review summarizes recent DFT studies on bifunctional electrocatalysts, including carbon-based materials, single-atom catalysts, transition-metal systems, and transition-metal oxides for ORR/OER applications in rechargeable zinc-air batteries. It discusses transition-metal-based catalysts, which offer strong catalytic activity; carbon-based materials and metal-free nitrogen-doped carbon catalysts, which are lightweight and inexpensive; metal-nitrogen-doped carbon catalysts, which show excellent stability and high activity; and transition-metal oxides, which are abundant and durable alternatives. By comparing these materials, DFT studies help explain how oxygen binds to catalyst surfaces, how reaction steps proceed, and how electronic properties affect performance. These insights are guiding the development of efficient, stable, and low-cost cathode materials for next-generation zinc-air batteries.</p>