Background Facial beauty depends on the form, proportion, and position of various units of the face. In terms of the frontal view and facial profile, the chin is the most prominent aesthetic element of the lower third of the face. Many methods have been implemented to obtain good proportions of the lower face. In this study, we applied the T-shaped genioplasty method to correcting chin deformities. Methods All of the procedures in 9 cases were performed under general anesthesia. For genioplasty, a horizontal cutting line and 1 or 2 vertical cutting lines were drawn 5 mm below the mental foramen. Osteotomed bone segments of the chin were used for horizontal widening using bone grafts or for horizontal shortening. Likewise, they were used as bone grafts for vertical lengthening or vertical shortening. The bone segments were approximated in the midline and held in place using miniplates. Results The postoperative appearance of the 9 cases showed that the lower third of the face had been naturally changed. At the same time, vertical lengthening or shortening, and horizontal widening or shortening could be implemented during the operation. Satisfactory results were obtained based on reviews of the patients' preoperative and postoperative photographs. The patients were also satisfied with the outcomes. Conclusions Using T-shaped genioplasty, we efficiently adjusted the shape and position of the chin to obtain good proportions of the lower face and change its contour to obtain an aesthetically appealing oval face in accordance with East Asians' aesthetic preferences.