Introduction Lingual thyroid is a rare embryological abnormality that occurs as a result of failed descent of the thyroid gland. Case report We report the case of a 39-year-old male with an incidental finding of a lingual thyroid during intubation for surgery for lower limb fractures. A sleep study indicated an RDI of 38.6, consistent with severe sleep apnoea. The ectopic thyroid was excised via a suprahyoid approach, with resolution of apnoeic symptoms post-operatively. A follow-up sleep study subsequent to his operation confirmed an RDI of 3.7. Conclusion This is the first time a lingual thyroid causing sleep apnoea has been studied with pre- and post-treatment sleep studies. This is also the first recorded instance of lingual thyroid causing sleep apnoea has been recorded in a male.