has become a global public health issue, serving as both a cause and consequence of metabolic disorders and various chronic diseases, and is regulated by multiple biological processes. In recent years, protein lactylation, a novel post-translational modification (PTM), has been found to directly or indirectly participate in the pathophysiology of obesity through multiple physiological and pathological processes, including gene transcription, cell fate, inflammation, tumor development, and metabolism. It has gradually become a research hotspot. However, there is currently a lack of systematic reviews on the regulatory mechanisms of protein lactylation in obesity. This review begins with the production and function of lactate, systematically introduces the biochemical basis, detection methods, and biological functions of lactylation, and then explores its involvement in obesity by examining four key aspects: lactylation-mediated inflammatory signaling pathways, the induction of insulin resistance, its effects on glucose uptake and glycolysis, and its interference with lipid metabolism. The focus is placed on its potential roles and mechanisms in obesity regulation, and finally, potential future research directions and challenges are proposed.