A review of the literature on Rett syndrome (RS) for school-based professionals is presented from a behavioral perspective. A description of RS is provided, including distinctive physical, behavioral, and emotional features, diagnostic criteria for classic and formes frustes forms of RS, and stages of the disorder. The similarities and differences between RS and autism are reviewed. Controversies regarding the classification of RS are presented, including whether RS should be classified as a neurological or psychiatric condition and whether RS should remain classified as a pervasive developmental disorder. Last, a variety of options for the treatment of RS are discussed.