In this article, we report a case of a giant-cell tumor of the patella which occurred in an atypical location with soft tissue involvement, which makes our case clinically and radiologically unique. A 24-year-old patient was admitted to our clinic with a complaint of anterior knee pain. Radiological examination and percutaneous fine needle biopsy showed a diagnosis of giant-cell tumor of the patella. The patient underwent patellectomy with en-bloc resection of the lesion with totally involved soft tissue components and the extensor mechanism was reconstructed with two Achilles allografts. After surgery, the diagnosis was confirmed by histopathological examination. At 12 months, the patient had no recurrence with 110° flexion and 30° extension of the range of motion of the knee. Lysholm knee score was 72. At 90°/sec isokinetic muscle strength test, the muscle strength loss was found to be 51.1% in the extensor and 21.1% in the flexor, compared to non-involved knee. In conclusion, giant cell tumors are difficult to treat, as they are destructive lesions with high recurrence rates. Despite reduced range of motion and muscle strength, based on our study results, we believe that our surgical treatment modality may be an alternative for the treatment of patellar giant cell tumors.