OBJECTIVE To review current classification systems for adolescent and adult scoliosis. METHODS The literature was reviewed in reference to scoliosis classification systems for adolescent and adult scoliosis. RESULTS There are multiple classification systems for scoliosis. Classification of scoliosis is dependent on patient age, spinal abnormality, scoliotic curve, and global spinal alignment. To date, classification systems have focused predominantly on adolescent idiopathic scoliosis or adult/degenerative scoliosis; a single classification system evaluating scoliotic deformities of different ages and spinal abnormalities has not been identified. CONCLUSION The importance of scoliosis classification schemes lies in their ability to standardize communication among health care providers. With regard to the classification of adolescent scoliosis, the Lenke system has addressed many of the significant limitations of the King system and is now the standard classification scheme. Classification schemes for adult scoliosis have been reported only recently, and each offers specific advantages (the simple pathogenesis-based system of Aebi, the strong clinical relevance of the Schwab system, and the richly descriptive Scoliosis Research Society system). This article highlights the salient features of currently used scoliosis classification systems.