In recent years, the incidence of metabolic diseases, such as obesity and diabetes, has steadily increased with continuous social development. These diseases substantially compromise individuals' quality of life and impose a significant socioeconomic burden. Furthermore, chronic metabolic dysregulation readily triggers various life-threatening cardiovascular complications. As the core of energy metabolism, mitochondria are closely associated with metabolic diseases and related cardiovascular complications. Sirtuin 3 (SIRT3), a mitochondrial deacetylase, regulates the majority of mitochondrial proteins through deacetylation modifications. This process enables it to be involved in various mitochondrial functions and modulate the pathological processes of metabolic diseases such as obesity and diabetes, as well as their cardiovascular complications. This review therefore focuses on SIRT3, summarizing the latest research on its relationship with metabolic diseases and related cardiovascular complications, with the aim of providing a reference for future studies.