Tillaux fractures in adults are rare and, if unrecognized, can lead to ankle fracture healing complications, early progression of arthritis, and limited ankle movement caused by pain and degenerative changes. The Tillaux fracture was first described by Paul Tillaux as an external rotation injury of the ankle, involving an avulsion fracture of the distal anterolateral tibia. This fracture can be easily overlooked on plain radiographs in the adult. A high index of suspicion for this type of fracture pattern along with the use of computed tomographic scanning can help confirm the suspected diagnosis, rule out other tibial injuries, and provide more information on the best course of action. Historically, Tillaux fractures have been more common in adolescents because of the open tibial epiphyseal plate. Once the epiphyseal plate fully closes, skeletal maturity is achieved, thus making it extremely unusual for the anterior tibiofibular ligament to cause an avulsion fragment of the distal anterolateral tibia. Because of how uncommon this type of fracture is in adults, it has rarely been reported in our literature. We reviewed the literature and present a case report of this rare fracture injury.