Background: Subependymal giant cell astrocytoma (SEGA) is a rare, benign neoplasm predominantly associated with tuberous sclerosis complex. Clinical outcomes have largely been conveyed via small- and medium-sized case series. Methods: With the Surveillance, Epidemiology, and End Results Program (SEER)–18 registry database, information from all patients diagnosed with SEGA from 2004 to 2013 was obtained (age, sex, race, marital status, tumor size, tumor location, occurrence of surgery, receipt of radiation, and follow-up data). Age-adjusted incidence rates and overall survival (OS) were determined. Cox proportional hazards model was used for both univariate and multivariate analyses. Results: The overall incidence of SEGA within the SEER-18 database is 0.027 per 100,000 person-years (95% confidence interval, 0.024–0.031). A total of 226 cases were identified. For OS, univariate analysis revealed age younger than 18 years (hazard ratio [HR], 0.214; P = 0.004) and occurrence of surgery (HR, 0.328; P = 0.039) were significant positive prognostic factors. Sex, marital status, race, tumor size, tumor location, and receipt of radiation did not exhibit significant relationships. Interestingly, subanalysis for extent of resection to gross total resection did not show benefit. Multivariate analysis revealed that both age younger than 18 years (HR, 0.193; P = 0.002) and occurrence of surgery (HR, 0.286; P = 0.021) remained significant. Conclusions: Based on our analysis, younger age and occurrence of surgery are significant independent factors associated with better OS. There was no support for radiation. © 2018 Elsevier Inc.