Abstract Purpose Surgical site infection (SSI) is common after laparoscopic appendectomy, resulting in prolonged hospital stay and increased costs. This study examined the relationship between body composition parameters and risk of incisional SSI in patients with complicated appendicitis. Methods We included 411 patients who underwent laparoscopic surgery for complicated appendicitis at a single institution between March 2015 and October 2023. Body composition parameters were derived from preoperative computed tomography (CT). A nomogram was constructed based on the independent predictors of incisional SSI. Results Overall, 45 (10.9%) patients developed incisional SSI. Visceral fat area (VFA) was independently associated with risk of incisional SSI (hazard ratio 1.015, 95% confidence interval 1.010–1.020, P