Posterior teeth exhibiting a transverse discrepancy are said to be in crossbite. This abnormal bucco-lingual relationship is usually viewed as affecting one side, but it is really a bilateral problem. There is a multifactorial etiology for this. Early diagnosis by the treating dentist is essential for proper treatment. If not detected early, surgically assisted rapid palatal expansion is needed to correct the transverse discrepancy. Through a series of osteotomies, along with orthodontic appliance therapy, it can be corrected. On such case is presented here. The three main objectives of this treatment are to correct the posterior crossbite; to reduce crowding, and to form a stable occlusion. As shown by this case example, surgically assisted rapid palatal expansion is a safe and effective means of correcting posterior crossbites.