Children with acute viral croup commonly present to EDs or primary care providers. The vast majority of patients will present with mild croup without showing any signs of upper airway obstruction. The diagnosis of croup should be made on clinical grounds, but potentially fatal (even if rare) diagnoses such as bacterial tracheitis or epiglottitis should be kept in mind. All children presenting with croup should be treated with oral dexamethasone to reduce the severity of symptoms, rate of revisits, or admissions to the hospital and to lessen patient and parental anxiety and economic burden. Children exhibiting symptoms of upper airway obstruction should be treated with nebulized epinephrine and observed for at least 2 hours after treatment before being discharged home. With knowledge of the basic evidence-based principles of emergency management outlined in this article, the emergency clinician will be able to successfully identify and manage the different levels of severity of croup.