Free flaps based on static slings principles cannot provide esthetic and functional outcomes at a desired level in total or close to total lip loss. Therefore, dynamic methods have become a current issue in recent years and especially the idea of functional gracilis free muscle flap has been suggested. In this study, we present a case of a successful total lower lip repair with this flap.In a 78-year-old female patient who was diagnosed with squamous cell carcinoma involving the entire lower lip, bilateral modified radical neck dissection and full-thickness total resection with 1 cm surgical margin so as to include both commissures of the tumor were performed and then a free gracilis muscle flap was transferred from the same side. After microvascular anastomoses, the motor nerve of the flap was coapted to the marginal mandibular branch of the fascial nerve. The entire intra- and extraoral surfaces of the flap were covered with a partial-thickness skin graft which was taken from the right thigh. There was no any intra- or early postoperative complication. The skin graft and flap survived without any problem.In the controls of the patient who was followed-up for 8 postoperative months, it was observed that the gracilis muscle flap was well-adapted to its place, gained a very good tonus, its volume reduced over time and reached to ideal dimensions, and the overlying skin graft provided a good color and texture match with the surrounding tissues. The motor activity of the muscle was monitored with the Tinel's test. The speech and facial expressions of the patient were very clear. Despite the patient has an edentulous mandible and was not using prosthesis, her feeding with fluid and solid foods was free of problems, oral competence was highly sufficient, and there was no any drooling. Esthetic appearance was very good and intraoral vestibular depth was sufficient. The mouth opening was 3 cm. When comparing with upper orbicularis oculi muscle on the electroneuromyography (ENMG) ordered at the 8th month, a similar nerve conduction time (3.3 versus 3.8 ms) and contraction amplitude (0.5 versus 0.4 mV) values were obtained from the gracilis muscle. Follow-up of the patient is still continued with no tumor recurrence observed during this period.Being the real dynamic flap and its tonus of the functional gracillis free muscle flap in opposite to the static methods provides a significant superiority over the other options in terms of oral functions; moreover, the overlying skin graft presents a very good color and texture harmony aesthetically. This method is a candidate to be an exclusive surgical technique in the repair of total or close to total lip losses in the future.