Osteochondromas are common benign cartilage capped osseous surface projections, generally arising from the metaphysis of long bones. It may occur anywhere with enchondral ossification. The presence of cortical and medullary continuity of the tumor with the underlying bone is a pathognomic feature  suggesting the diagnosis. Osteochondromas may be solitary or multiple. The multiple form is an autosomal dominant syndrome referred to as hereditary multiple exostosis (HME). Solitary lesions can be primary or secondary. Primary osteochondromas develop spontaneously with no precipitating etiology.   secondary osteochondromas can result from Salter- Harris fracture, post-surgery or radiation therapy. Here we are presenting a case of 8 year old female child with left temporomandibular joint  osteochondroma with a history of injury to her left side of her face following self-fall 4 years back. She presented with gradually progressive; inability to open her mouth for last one year. She was managed with GAP arthroplasty with TFL graft with excision of left TMJ osteochondroma and later on k-wiring with arch bar fixation.  She was adviced for physiotherapy (mouth-opening exercises) upon discharge. Virchow postulated that osteochondroma may result from the separation of a small piece of cartilage from the growth plate and subsequent independent growth. Muller postulated that small cartilage nodules formed from the cambium layer of the periosteum might lead to osteochondroma formation. Keith attributed formation of osteochondroma to a defect in the periosteal ring that allows for abnormal expansion and development of the benign lesion. Geshickter and Copeland postulated that the clusters of embryonic connective tissue at the point of tendinous attachments could convert to osteochondroma with repetitive stress. Langenskiold postulated that osteochondroma occurs when limited portion of the undifferentiated cell layer of the growth cartilage are displaced peripherally towards the metaphysis. Most accepted Lichtenstein theory  states that the periosteum has the potential to develop osteoblasts and chondroblasts and that osteochondroma develops by metaplastic change in periosteum. Trauma to the condyle might be trigger to such changes. Several authors have identified  traumatic event prior to the formation of osteochondroma. There is a need for further experimental studies so as to clarify traumatic etiology for osteochondromas.