The purpose of this case report is to highlight an unusual diagnosis and mechanism of injury. Vertical patellar dislocation is an uncommon entity. Relatively few cases have been reported in the literature, and most of these have occurred in adolescent boys who have sustained a direct blow to the knee while engaging in some form of contact sport. The case reported here is a vertical patellar dislocation that happened to a 10-year-old girl without any trauma. This is an unusual case and seemingly atypical for a vertical patellar dislocation. The knowledge of this diagnosis might assist clinicians in the understanding of unlikely mechanisms of injury in the assessment and treatment of this musculoskeletal disorder.