This study was performed to clarify whether the superthin anterolateral thigh (ALT) flap is an appropriate choice for head and neck reconstructions requiring thinner and more pliable flaps. Data of patients who underwent head and neck reconstruction from January 2020 to December 2022 were retrospectively collected. Nine patients (4.2%) underwent reconstruction with a superthin ALT flap. All the flaps survived with no cases of total or partial necrosis. Six patients treated with superthin ALT flaps and 15 patients treated with conventional ALT flaps who underwent oral cavity reconstruction were compared. The mean body mass index was significantly higher in the superthin flap group than in the conventional ALT flap group (25.2 vs 21.2kg/m2, respectively; P = 0.04). The rate of postoperative complications requiring debridement was 0% and 13% (P = 0.37). The mean postoperative Hirose score was 9.7 and 8.7 (P = 0.17). The mean postoperative Functional Oral Intake Scale score was 6.7 and 5.9 (P = 0.12). Secondary flap refinement surgery after facial skin reconstruction was performed in 0 of 2 patients (0.0%) in the superthin flap group and 4 of 52 patients (7.7%) in the conventional ALT flap group (P = 0.04). Oral cavity reconstruction with superthin ALT flaps did not increase the incidence of postoperative flap necrosis and resulted in comparable postoperative function. In addition, superthin ALT flaps did not require additional flap refinement surgeries after facial skin reconstruction. The superthin ALT flap is a safe and reliable choice for obese patients with thick thigh subcutaneous tissue.