Genu valgum is a common orthopaedic problem in children. The vast majority of cases are physiologic variants, which resolve normally. However, there are pathologic entities due to both focal and systemic processes in which the deformity often progresses and usually requires treatment. Differentiating between the two forms is facilitated by a thorough understanding of the natural history of the development of the tibiofemoral angle in children. In this review, an approach to the evaluation and diagnosis of genu valgum is presented, and therapeutic alternatives are discussed.