Sliding genioplasty is an established surgical technique used in orthognathic and facial plastic surgery. It enables the correction of multiple bone discrepancies, such as pro- or retrogenia, as well as asymmetries. Chin narrowing procedures are beneficial in gender-affirming surgery for male-to-female patients, as they provide a more triangular shape to the lower face, which is considered more feminine. However, <
10% of transgender patients undergo female-to-male transition where the lower face needs to be more squared, with prominent angles and a strong chin. Moreover, cisgender males are increasingly opting for facial aesthetic surgery to enhance their masculine appearance. This study presents the protocol for lower face masculinization with a modified chin osteotomy that may be used in conjunction with custom mandibular angle implants.