The present review article aims at providing an update on the basic science and clinical information underlying the use of nocturnal braces for adolescent idiopathic scoliosis. The use of nocturnal braces has been dictated by the encouraging results recorded by some studies on part-time bracing, combined with increasing concerns on poor patient compliance noted with the use of full-time bracing. The cardinal feature of nighttime braces lays in their ability to hypercorrect the scoliotic curvature, thereby eliminating the asymmetric water accumulation that occurs in the apical and adjacent intervertebral discs, thus restoring a close-to-normal force application through the Hueter-Volkmann principle and preventing curve progression. The two nighttime braces mostly used hypercorrect the spine through different mechanisms, one acting by bending the spine and the other by the application of opposing forces. Based on the clinical results available, nighttime braces constitute an attractive option for single-major lumbar/thoracolumbar curves not exceeding 35 degrees in magnitude. Multi-center, randomized studies using strict criteria set forth by the Scoliosis Research Society and the Study group On Scoliosis Orthopaedic and Rehabilitation Treatment are needed to better define the role of nocturnal bracing in the conservative treatment of adolescent idiopathic scoliosis.