Genetics and epigenetics play critical roles in the progression and manifestation of diabetes mellitus. Genetic factors contribute significantly to an individual’s susceptibility to developing diabetes, influencing aspects such as insulin production, glucose metabolism, and pancreatic function. Variations in genes associated with insulin secretion (e.g., TCF7L2) and insulin sensitivity (e.g., IRS1) can predispose individuals to type 2 diabetes. Additionally, epigenetic mechanisms, which involve modifications in gene expression without altering the underlying DNA sequence, are increasingly recognized as key players in diabetes pathogenesis. Factors such as DNA methylation, histone modifications, and non-coding RNA regulation can influence gene activity related to glucose homeostasis and insulin signaling pathways. Understanding the interplay between genetic predisposition and epigenetic regulation provides valuable insights into the heterogeneous nature of diabetes mellitus and offers potential avenues for personalized treatment strategies and disease management.