Osteochondroma is one of the most common benign bone tumors. However, it rarely develops in a tendon sheath, joint capsule, or extraarticular(noncomminucating) bursa. Extra-articular tenosynovial osteochondroma is usually evident in the hand, wrist, foot, or less frequently, knee. Authors are reporting a case of tenosynovial osteochondroma in the patellar tendon sheath, which was managed by en bloc excision, contained the tenosynovial membrane with excellent results.