Hypoglossal nerve palsy (HNP) is an uncommon neurological abnormality that can provoke characteristic clinical signs, including unilateral atrophy of the tongue musculature. We present the case of a healthy 11-year-old Korean male who was admitted to the outpatient department of our institution with acute onset dysarthria, tongue fasciculations, and right-sided tongue weakness upon awakening. His evaluation included a virology work-up, neck magnetic resonance imaging (MRI), brain MRI, and otorhinolaryngological physical examination; all tests were normal and showed no evidence of inflammation. Fifteen days after the onset of symptoms, the patient recovered completely. Herein, we report a case of idiopathic isolated HNP in a Korean male.