Paraarticular chondroma of the knee is a very rare benign tumor that seems to develop from cartilageous metaplasia. This lesion should be differentiated from calcifying soft tissue lesions like tumoral calcinosis, and cartilageous lesions like chondrosarcoma and synovial chondromatosis. We experienced a case of paraarticular chondroma of the knee in an Osgood-Schlatter disease patient.