Epigenetic mechanisms play a crucial role in the development and progression of nonalcoholic fatty liver disease (NAFLD), especially among lean individuals. The research on related epigenetic mechanisms has provided new clues and directions for revealing the underlying causes and treatment strategies of NAFLD. This article introduces the role of epigenetics in the development and progression of NAFLD among lean individuals in recent years, analyzes the latest research advances in the epigenetics of NAFLD in this population, and briefly describes the basic concepts of epigenetics, including DNA methylation, histone modifications, and non-coding RNA regulation. This article also discusses how epigenetic alterations impact the pathogenesis, disease progression, and treatment strategies of NAFLD in lean individuals.