Objective: To evaluate the success of sole medical therapy (MT) versus surgical therapy (ST) in patients with both clinically and radiographically confirmed peritonsillar abscess (PTA). To also determine treatment safety based on abscess size, and identify predictors of treatment failure. Methods: This was a retrospective cohort of 3 hospitals in a single academic health system. A total of 214 immunocompetent patients diagnosed with uncomplicated PTA underwent a contrasted CT scan of the neck. About 87 patients were treated with sole MT (intravenous antibiotics and steroids), and 127 patients were treated with ST (MT plus drainage). Results: Treatment failure occurred in 8.0% of the MT group and 7.9% of the ST group ( P = 1.00). In PTAs <2 cm, treatment failure occurred in 5.3% of the MT group and 5.0% of the ST group ( P = 1.00). In PTAs ≥2 cm, treatment failure occurred in 13.3% of the MT group and 9.0% treated with ST ( P = .53). Size ≥2 cm (OR – 3.46, P = .08) and IV clindamycin as sole IV antibiotic (OR – 2.46, P = .15) trended toward predicting treatment failure. In addition to those considered failures, 7.0% of the ST group returned to the ED with pain versus 0% of the MT group ( P = .01). Conclusion: Frequency of treatment failure was not significantly different among patients receiving MT and ST. Abscesses ≥2 cm in size were more likely to fail in both groups and ST was not statistically superior. Sole MT for uncomplicated PTA may help reduce unnecessary procedures and healthcare costs.