Pterygium is a type of benign uncontrolled growth of the conjunctive tissue that lays over the sclera. It can significantly alter visual function in advanced cases and become inflamed, leading to redness and irritation in the area. Although the exact etiology of pterygium remains uncertain, recent advances have provided important insight into the pathogenesis of pterygium. These studies indicate that tumor suppressor gene p53 and other genes associated with DNA repair, cell proliferation, migration and angiogenesis are critical for the development of pterygium. In addition, Human papillomavirus infection has been shown to be a risk factor in some populations. In this article, the current understanding of the pathogenesis of pterygium is reviewed.