We report an unexpected failed laryngeal mask airway in a patient with unrecognized lingual tonsil hypertrophy (LTH). A 19-year-old obese woman presented for extraction of multiple teeth via intravenous general anesthesia. Surgery was interrupted due to a laryngospasm midway through the procedure. The laryngospasm required the existing laryngeal mask airway to be removed so the patient could be suctioned. Although it is unclear the extent of obstruction caused by LTH, the surgery had to be postponed due to the discovery of enlarged lingual tonsils, which prevented endotracheal intubation. One reason for unexpected difficult airways is attributed to LTH. It is recognized that LTH is more common in patients with obstructive sleep apnea; however, LTH also has an increased prevalence in obese children with prior palatine tonsillectomies or adenoidectomies. Unexpected LTH can complicate general anesthesia by making placement of a laryngeal mask airway difficult. Thus, further research needs to be conducted to gain a deeper understanding on how to reduce the risks presented by LTH during sedation surgeries.