Familial hypercholesterolemia is a genetic lipid disorder characterized by elevated levels of low-density lipoprotein cholesterol and an increased risk of premature atherosclerotic cardiovascular disease. Traditionally considered a monogenic disorder caused by mutations in genes involved in low-density lipoprotein metabolism, advances in molecular genetics have revealed more complex genetic architectures, including oligogenic and polygenic forms. Oligogenic familial hypercholesterolemia results from the interaction of multiple rare variants across genes involved in lipid metabolism, while polygenic hypercholesterolemia is caused by the cumulative effect of numerous common genetic variants that modestly increase low-density lipoprotein cholesterol levels. These genetic patterns influence disease severity, clinical diagnosis, and therapeutic approaches. This review discusses the epidemiology, genetic mechanisms, clinical manifestations, diagnostic strategies, and treatment options for oligogenic and polygenic familial hypercholesterolemia, emphasizing the importance of early detection and aggressive lipid-lowering therapy to prevent cardiovascular complications.