Currently, water electrolysis has attracted significant attention as an environmentally benign hydrogen production technology. However, its practical implementation was substantially hindered by the sluggish kinetics of the four-electron/proton-coupled oxygen evolution reaction (OER), necessitating the development of cost-effective OER catalysts to improve overall reaction efficiency. This review systematically elucidated the OER mechanisms, with particular emphasis on the reaction pathways and key intermediates in different electrolytes. Focusing on alkaline media, recent advances in OER catalysts were comprehensively summarized, including noble metals, transition metal-based materials, monometallic metal-organic frameworks (MOFs), bimetallic MOFs, MOF derivatives and MOF-based composites. Future perspectives were proposed regarding mechanistic investigations and performance optimization strategies, aiming to guide the design of next-generation OER catalysts.