Context .- Ocular surface squamous neoplasia (OSSN) is the most common tumor of conjunctival epithelium associated with risk of permanent visual impairment. It includes conjunctival intraepithelial neoplasia and squamous cell carcinoma. Although American Joint Committee on Cancer-TNM (AJCC-TNM) staging is commonly used in various tumors, it has only recently been described for OSSN. Objectives .- To evaluate the prognostic relevance of AJCC-TNM staging and the clinicopathological features in OSSN. Design .- Sixty-four histopathologically proven cases of OSSN (20 conjunctival intraepithelial neoplasia and 44 squamous cell carcinoma) were included in the study. The AJCC-TNM staging and clinicopathological features of OSSN cases were recorded. Patients were followed up for 17 to 40 months (median, 32 months). Univariate and multivariate analyses were performed to determine the prognostic value of various clinicopathological features. Results .- Longer sunlight exposure (P = .01), diffuse growth pattern (P = .02), larger tumor size (≥2 cm) (P = .03), histopathological diagnosis of squamous cell carcinoma (P = .02), and orbital invasion or invasion of adjacent structures (T3 or T4) (P < .001) emerged as significant predictors of reduced recurrence-free survival. Using multivariate analysis, a higher T category (T3 or T4) was the most important prognostic indicator of a poor outcome. Conclusions .- A higher T category (T3 or T4) is an important predictor of clinical outcome, and the use of the AJCC-TNM staging system is recommended in the management of all patients with OSSN. Longer sunlight exposure, larger tumor size (≥2 cm), orbital invasion or invasion of adjacent structures (T3 or T4), and a histopathological diagnosis of squamous cell carcinoma are other clinicopathological features of prognostic relevance in patients with OSSN.