Unicameral bone cyst (UBC) is a benign cystic lesion most commonly diagnosed in the proximal aspects of the humerus and femur of growing children. Medullary venous obstruction is the leading pathogenesis theory, resulting in fluid accumulation, bone resorption, and cortical thinning. Most UBCs are asymptomatic and likely go undiagnosed, while the most common presentation is a pathologic fracture. UBC of the proximal femur exhibits unique characters and complications. Post-excision stabilization of the cyst is recommended to avoid malunion and facilitate post-operative rehabilitation and an earlier return to normal activities. In the present case report, surgical treatment of a pathological neck of the femur fracture following a unicameral bone cyst was managed with internal fixation of the proximal femoral plate with bone grafting, which showed a good clinical and radiological outcome.