Mumps virus infection primarily affects the salivary glands and may incur various complications. Laryngeal edema is such a rare complication that few adult cases have been reported. We report the first known pediatric patient with mumps with laryngeal edema. An 8-year-old boy developed dyspnea after a rapidly progressive swelling of his face and neck. Laryngoscopy revealed edematous changes in the supraglottic and subglottic regions, and computed tomography confirmed significant laryngeal edema in addition to swelling of the cervical soft tissue and the salivary glands. Laboratory findings revealed a high serum amylase level and confirmed the diagnosis of mumps. Intravenous steroid administration alleviated the dyspnea, although the patient required temporary tracheal intubation to maintain airway patency. He did not need tracheotomy and did not experience any other complications. Laryngeal edema must be regarded as a rare, potentially life-threatening complication of mumps. When mumps is diagnosed with significant swelling of the neck, an emergency airway should be established to prevent airway obstruction.