Introduction Peritonsillar abscess is a common complication to acute tonsillitis in younger adults. The primary treatment is surgical drainage, but it can be challenging to distinguish cellulitis from peritonsillar abscess on a standard clinical examination. This study aims to explore whether a novel technique for transoral ultrasound can improve the diagnostic accuracy and guide successful surgical drainage in patients with peritonsillar infections. Methods Patients referred to departments of Otorhinolaryngology, Head and Neck Surgery at Rigshospitalet with peritonsillar abscess was offered a transoral ultrasound as a supplemental to their standard clinical examination. The ultrasound exam was performed with a bk5000 machine (BK Medical®) and a Burr-Hole N11C5s transducer with an in-plane needle guide attached. The proportion of successful needle aspirations, complications, and diagnostic accuracy was evaluated. Results We included eighteen patients in the analysis, and all the patients tolerated the transoral ultrasound exam. Nine of the patients had peritonsillar abscess, while six had tonsillitis/peritonsillar cellulitis and three mononucleosis. Eleven patients had needle aspirations performed, of which two were without aspiration of pus. The sensitivity was found to be 100%, and the specificity was 78%. Conclusion Point-of-care transoral ultrasound was feasible and without complications in this study. Further, we found clinical benefits of adding transoral ultrasound to the diagnostic workup of patients with peritonsillar infections.