Thumb hypoplasia is part of a spectrum of radial longitudinal deficiencies involving the upper limb. Systemic involvement of other organ systems is not uncommon, thus requiring a team approach to management. Because of the variety of anatomic abnormalities associated with thumb hypoplasia, clinical and intraoperative evaluation of the thumb must be precise. Effective management of thumb hypoplasia requires an understanding of the embryology, epidemiology, classification, presentation, and management options. Management, which is primarily determined by the grade of thumb hypoplasia, may include nonsurgical techniques, reconstruction, pollicization, and, recently, microsurgical procedures.