Bilateral simultaneous avulsion fractures of the anterior tibial tubercle (ATT) are extremely rare. Since the first description in 1954, 15 similar cases have been reported. We report a further case in a 16-year-old boy who sustained simultaneous bilateral tibial tubercle avulsion fractures (Watson-Jones Type III) from jumping during a gymnastics session. The right knee presented an associated partial avulsion of the patellar tendon. Both knees were treated successfully by open reduction and internal fixation with two cannulated screws. The recovery of the patient was complete; the screws were removed six months later. After one year follow-up, the patient had no complaint and had resumed his sporting activity.