IMPORTANCE Resection of the depressor septi in rhinoplasty has been used to correct the smiling deformity. Studying the effects of this maneuver on the upper lip length is important for operative planning, as well as for patient counseling. OBJECTIVE To define an approach to the resection of the depressor septi muscle during functional and aesthetic rhinoplasty and to determine whether performing this maneuver causes any measureable change in the length of the upper lip in the repose position. DESIGN, SETTING, AND PARTICIPANTS A retrospective medical record review and photographic analysis were performed on 36 patients who had undergone rhinoplasty involving resection of the depressor septi by either of 2 of the investigators at a tertiary care academic center and a private practice between 2010 and 2013. All maneuvers performed during the procedure were recorded. Preoperative photographs were compared with postoperative photographs using Adobe Photoshop, and percent change in upper lip length was calculated. INTERVENTION Rhinoplasty involving resection of the depressor septi. MAIN OUTCOME AND MEASURE Percent change in upper lip length, calculated by measuring the ratio between upper lip length and intercanthal distance and comparing the preoperative and postoperative ratios. RESULTS Thirty-six patients were evaluated, including 22 men and 14 women. Postoperative photographs were taken a mean (range) of 7.06 months (7 days to 2 years) after surgery. The mean change was a 1.74%decrease in upper lip length; 24 patients (67%) had a decrease (mean [maximum], 5.89% [21.22%]), and 12 patients (33%), an increase (mean [maximum], 6.55%[12.68%]) in upper lip length. Compared with the preoperative lip length, the mean (95%CI) postoperative lip length was 100.09% (97.35%-102.83%) in women vs 95.37% (90.86%-99.88%) in men (P = .07). No predictable factors determined whether a patient would develop a postoperative increase or decrease in upper lip length. CONCLUSIONS AND RELEVANCE Resection of the depressor septi muscle during rhinoplasty is a well-documented maneuver often used in the treatment of the ptotic tip and smile deformity. This descriptive study showed that resection of the depressor septi muscle has an unpredictable but small effect on upper lip length in the repose position.