IMPORTANCE Further investigation is needed in the outcomes of currently available treatment for T3 glottic squamous cell carcinoma (SCC), a unique type of laryngeal cancer. OBJECTIVE To compare overall survival (OS) and functional outcomes among patients with T3 glottic SCC receiving nonsurgical and surgical management. DESIGN, SETTING, AND PARTICIPANTS This secondary analysis used data from the Surveillance, Epidemiology, and End Results (SEER) registry and Medicare databases. All patients with T3 glottic SCC who received a diagnosis from January 1, 1992, to December 31, 2010, were included. Data were analyzed from April 2014 to August 2015. INTERVENTIONS Surgery with or without adjuvant radiotherapy and/or chemotherapy. MAIN OUTCOMES AND MEASURES Five-year OS and functional outcomes. RESULTS Among the 487 patients identified with T3 glottic SCC (418 men [85.8%]; 69 women [14.2%]; median age, 74.3 [interquartile range, 70.4-80.6] years), the 5-year OS for nonsurgical management, surgery alone, and surgery plus adjuvant treatment were 36% (95%CI, 30%-42%), 41%(95%CI, 30%-53%), and 41%(95%CI, 32%-51%), respectively. Multivariable analyses revealed an adjusted hazard ratio for OS of 0.68 (95%CI, 0.49-0.94) for patients receiving surgery alone vs nonsurgical management and 0.75 (95%CI, 0.57-0.98) for patients receiving surgery plus adjuvant treatment vs nonsurgical management. Gastrostomy tube dependence was highest in patients receiving surgery plus adjuvant treatment (30 of 98 patients [30.6%]). Tracheostomy dependence was highest in patients receiving chemoradiotherapy (34 of 92 patients [37.0%]). CONCLUSIONS AND RELEVANCE Overall survival showed a statistically significant and clinically meaningful improvement in patients with T3 glottic SCC who underwent surgery compared with a nonsurgical treatment. Furthermore, the data suggest that adjuvant and nonsurgical treatment result in a dysfunctional larynx; however, this association needs further study.