Importance: To our knowledge, there are no validation studies to date of the prognostic value of the AJCC Cancer Staging Manual, eighth edition (AJCC 8), criteria for eyelid and periocular squamous cell carcinoma. Objective: To determine the association of tumor (T) category in AJCC 8 with local recurrence, nodal metastasis, distant metastasis, and disease-specific survival (DSS) for eyelid and periocular squamous cell carcinoma. Design, Setting, and Participants: In this retrospective, single-center cohort study, 109 consecutive patients with eyelid and periocular squamous cell carcinoma treated from January 1999 to April 2018 were included. Patients with secondary involvement of the periocular region were excluded. Main Outcomes and Measures: Local recurrence, nodal metastasis, distance metastasis, and DSS. Results: Of the 109 included patients, 81 (74.3%) were male, and the median (range) age was 66 (40-91) years. At presentation, 43 patients (39.4%) had recurrent tumor, 4 (3.7%) had nodal metastasis, and 1 (0.9%) had distant metastasis. The median (range) follow-up was 23 (1-161) months. During follow-up, 11 patients (10.1%) developed local recurrence, 7 (6.4%) developed nodal metastasis, 2 (1.8%) developed distant metastasis, and 9 (8.3%) died of disease. The 5-year DSS rate was 87.7% (95% CI, 79.5-96.9). Chronic immunosuppression (hazard ratio, 47.24; 95% CI, 7.33-304.30; P <.001) and presentation with recurrent squamous cell carcinoma (hazard ratio, 5.22; 95% CI, 1.12-24.31; P =.04) were associated with local recurrence during follow-up. Of the 11 patients with local recurrence during follow-up, 7 (64%) had perineural invasion. T category was associated with nodal metastasis; clinical stage of T2c or worse at presentation was associated with higher risk of nodal metastasis and death of disease but not with a higher risk of local recurrence. Distant metastasis was associated with nodal metastasis at presentation (hazard ratio, 32.50; 95% CI, 1.97-536.40; P =.02) and during follow-up. A total of 33 patients (30.3%) had different T categories depending on whether disease was staged according to the seventh or eighth edition of the AJCC Cancer Staging Manual. Compared with AJCC 7, AJCC 8 showed a better predictive value in terms of local recurrence (T3, 17% vs 14%; T4, 11% vs 16%) and DSS. Conclusions and Relevance: These findings suggest that T category in AJCC 8 is associated with nodal metastasis and DSS. Immunosuppression and presentation with recurrent disease are associated with increased risk of future local recurrence. Patients with tumors of clinical stage T2c or worse at presentation are at increased risk of nodal metastasis and worse DSS and should undergo surveillance for nodal metastasis. Future studies, ideally prospective in design, could provide greater confidence in these findings.