Orthodontic techniques have revolutionized in the last decade and clear aligners play a major part in this. Earlier concept of using aligner treatment for mild cases has now been rejected due to development in auxiliaries, temporary anchorage devices, more refined computer programmed tooth movements, manufacturing techniques and materials. With the increasing accuracy of aligner treatment, need to understand the working biomechanics of clear aligners is of utmost important. This review articles gives a horse eye view of the biomechanics and the wide scope of malocclusion which can be treated with clear aligners.