Peritonsillar abscess is generally seen as a complication of acute tonsillitis in young subjects. It may, however, in rare cases reveal a malignant tumor of the tonsil: most often squamous cell carcinoma or, more rarely, lymphoma. We report a rare case of tonsillar lymphoma revealed by a peritonsillar abscess.A 66-year-old woman, without history of recurrent tonsillitis, was admitted for right peritonsillar abscess with fever. She underwent incision-drainage of the abscess with 10 days’ intravenous antibiotics. As tonsillar hypertrophy persisted, tonsillectomy was performed; histology with immunohistochemical examination found tonsillar lymphoma.Possible tumoral etiology should be considered in any peritonsillar abscess occurring in an atypical subject. Acute-stage tonsillectomy enables early diagnosis.