Orbital roof fractures after head injury is rare. Traumatic encephaloceles in the orbital cavity are even rarer, with only 24 cases published to date. We report the case of an adult with a post-traumatic orbital encephalocele. One day after a road traffic accident with head injury, the patient developed progressive pulsatile proptosis. Computed tomography and magnetic resonance imaging revealed an isolated blow-in fracture of the orbital roof with herniation of the left frontal lobe into the orbit. Neurosurgery to repair the orbital defect led to full recovery.