Osteopetrosis (OP) is a group of rare sclerosing bone dysplasia characterized by increased bone density. The benign autosomal dominant form is the most common type. It typically carries a full life expectancy, despite increased propensity for fractures and other musculoskeletal problems, particularly hip osteoarthritis. In the current literature, the youngest OP patient having hip osteoarthritis is 16 years of age and treated with total hip arthroplasty. Within the present study, a 16-year-old female patient with early-onset hip osteoarthritis treated with hip joint debridement and femoral head reshaping is presented. The pain relieved and hip joint movements recovered to almost normal range. At the final follow-up at 2 years after the surgery, the patient was still free of pain and ambulating without restriction. Hip joint debridement and femoral shaping may be beneficial in hip osteoarthritis secondary to OP in adolescents, and may delay hip arthroplasty in a young age.