The current review uses a developmental perspective to examine processes that may underlie and partially account for the association between anxiety disorders and disruptive behavior disorders among children and adolescents. We propose that one way to understand development of comorbid anxiety and disruptive behavior disorders is to examine symptoms that are precursors for or part of these syndromes, such as anxious symptoms and reactive aggression. We use a framework that considers these issues first at the syndrome or disorder level (e.g., anxiety disorders, disruptive behavior disorders), then at the symptom level (e.g., anxious symptoms and reactive aggression), and finally at the risk factor level (e.g., factors associated with anxious symptoms and/or reactive aggression). We apply various frameworks that have been put forth for understanding comorbidity of psychological syndromes to the co-occurrence of anxiety and disruptive behavior disorders and to the co-occurrence of reactive aggression and anxious symptoms where possible. We then identify gaps in the literature with regard to anxiety and reactive aggression, as well as anxiety and disruptive behavior disorders more generally. Finally, we provide a conceptual model describing how the relation of anxiety and reactive aggression may develop into clinically identifiable, comorbid anxiety and disruptive behavior disorders.