OBJECTIVE : As the incidence of autism spectrum disorder (ASD) increases, otolaryngologists are more likely to encounter patients from this population during tonsillectomy. The purpose of this study was to examine whether outcomes differ between pediatric patients with and without ASD in a national cohort of children undergoing tonsillectomy. Understanding these differences may be used to inform future approaches to improve clinical outcomes and healthcare costs. METHODS : Data for this study were obtained from the Kids Inpatient Database (KID) of the Healthcare Cost Utilization Project. We studied pediatric patients who underwent tonsillectomy during 2003, 2006, 2009, and 2012. Tonsillectomy was identified using ICD-9-CM diagnosis codes 28.2 (tonsillectomy without adenoidectomy) and 28.3 (tonsillectomy with adenoidectomy). ASD was identified using ICD-9-CM diagnosis code 299 (autism). Outcomes including complications, length of hospital stay, and total hospitalization costs. Analyses were performed using multivariable models. Propensity score matching was used to control for covariate imbalance between patients with and without ASD. RESULTS : In our sample of 27,040 patients, 322 (1.2%) had a diagnosis of ASD. After controlling for potential confounders, multivariable modeling suggested patients with ASD had a shorter LOS of 0.50 days (p < 0.0001), were less likely to experience complications (odds ratio 0.57, p = 0.001), and had lower associated costs of $1308 less (p < 0.0001). Propensity score matching confirmed the findings of the multivariable modeling. CONCLUSIONS : Although ASD alone does not appear to confer additional costs or morbidity, differences between children with and without ASD suggest the need for providers to address patients with ASD uniquely.