Anxiety disorders are the most common psychiatric conditions in children and adolescents, affecting nearly 1 in 12 children and 1 in 4 adolescents. Anxiety disorders include specific phobias, social anxiety disorder, separation anxiety disorder, agoraphobia, panic disorder, and generalized anxiety disorder. Risk factors include parental history of anxiety disorders, socioeconomic stressors, exposure to violence, and trauma. The U.S. Preventive Services Task Force recommends screening for anxiety disorders in children eight years and older; there is insufficient evidence to support screening in children younger than eight years. Symptoms of anxiety disorders in children and adolescents are similar to those in adults and can include physical and behavioral symptoms such as diaphoresis, palpitations, and tantrums. Care should be taken to distinguish symptoms of a disorder from normal developmental fears and behaviors, such as separation anxiety in infants and toddlers. Several validated screening measures are useful for initial assessment and ongoing monitoring. Cognitive behavior therapy and selective serotonin reuptake inhibitors are the mainstay of treatment and may be used as monotherapies or in combination. Prognosis is improved with early intervention, caretaker support, and professional collaboration.