Background: Infectious mononucleosis (IM) is known to present with upper airway obstructive symptoms; however, the association with lingual tonsillitis as a potential cause is rare. Case Presentation: We present a case of a 23-year-old male patient presenting with symptoms mimicking supraglottitis and later diagnosed as lingual tonsillitis complicating IM. Conclusion: It is imperative to keep lingual tonsillitis in sight in patient with symptoms of IM with airway compromise.