It is important for the oral and maxillofacial surgeon to understand the orthodontic decision-making process as it pertains to the orthognathic surgery patient to facilitate interprofessional communication. The orthodontic diagnostic process integrates the needs of the dentition, the requirements of facial balance, and the constraints of orthodontic mechanics to arrive at the best collective recommendation in each case. The orthodontic treatment objectives, extraction patterns, and types of mechanics used in orthognathic surgery cases may vary from those used in nonsurgical orthodontic regimens, in which the dentition is considered in the context of the largely immutable skeletal pattern. The goal of presurgical orthodontic treatment is to prepare the dentition for maximal surgical correction so that, at the time of surgery, the dental arches are compatible with the postsurgical position and facial balance is achieved.