Neurological complications may rarely occur in infectious mononucleosis (IM), including neuritis. All the cranial nerves can be implicated, probably as a consequence of the massive neurotropism of Epstein-Barr virus. Here, we describe a case of hypoglossal nerve palsy complicating IM in a 15-year-old girl. Hypoglossal nerve palsy presented with left deviation of the tongue. The patient was treated with steroids for several weeks, until complete resolution of the palsy.