Objective To explore the feasibility and effectiveness of free vastus lateralis flap combined with skin grafting for repairing small- and medium-sized lacunar defects in the non-weight-bearing area of diabetic foot. Methods Between January 2022 and October 2023, 8 patients (8 feet) with small- and medium-sized lacunar defects in the non-weight-bearing area of diabetic foot were admitted. There were 6 males and 2 females, with an average age of 64.3 years (range, 58-76 years). The duration of the diabetic foot ulcer ranged from 2 to 7 weeks (mean, 4.3 weeks). The wound was located between the metatarsal bones in 4 cases, on the medial side of the foot in 2 cases, on the lateral side of the foot in 1 case, and on the dorsal and lateral sides of the foot in 1 case. The length of wound was 4.0-12.0 cm, the width was 3.0-5.0 cm, and the depth was 1.2-2.0 cm. The free vastus lateralis flaps were designed to repair the wounds, and skin grafting covered the vastus lateralis flaps. The length of the vastus lateralis flap was 5.0-14.0 cm, the width was 3.5-6.0 cm, and the thickness was 1.0-1.5 cm. The donor sites of the muscle flaps were directly sutured. Results The time for vastus lateralis flaps harvested ranged from 30 to 80 minutes (mean, 55.0 minutes), and the total operation time ranged from 125 to 170 minutes (mean, 147.5 minutes). All muscle flaps and skin grafts survived successfully, and the wounds and the incisions at the donor sites healed by first intention. All patients were followed up 6-24 months, with an average of 12.8 months. The appearances of 3 patients who did not follow the doctor’s instructions for pressure treatment of the muscle flaps were a little bloated, and the rest had a good appearance. The texture of the muscle flaps was soft. There were linear scars at the donor sites. There was no recurrence of ulcers during follow-up. All patients could walk independently without limitation of daily activities at last follow-up. Conclusion The application of free vastus lateralis flap combined with skin grafting to repair small- and medium-sized lacunar defects in the non-weight-bearing area of diabetic foot has the advantages of simple operation and time-saving as well as small damage to the donor site, with good repair effect, especially for the elderly patients who are not suitable for prolonged anesthesia.