Viral bronchiolitis is the most common lower respiratory tract infection in infants and children under the age of 2. Respiratory syncytial virus (RSV) is the infecting agent in more than 50% of the cases. Usually the clinical course is uneventful and complications are uncommon. Secondary air leaks are a recognized rare complication of bronchiolitis, although the real incidence remains unknown. We report a case of a 21-month-old female that developed a spontaneous pneumothorax (PNO) with subcutaneous emphysema (SE) late in the course of RSV acute bronchiolitis. Additional investigation ruled out any underlying disease predisposing to spontaneous PNO. Physicians, especially those who work with small children, must be aware of this uncommon complication of bronchiolitis that may appear late in the course of the disease despite an initial clinical improvement.