We examine the lifetime comorbidity among anxiety disorders, and between anxiety disorders and other mental disorders, in a large (n = 1,507) community sample of high school students on whom extensive diagnostic data were available. Three diagnostic groups were formed: those with a lifetime anxiety disorder (n = 134); those with a nonanxiety disorder (n = 510); and those who had never met criteria for a mental disorder (n = 863). The intra-anxiety comorbidity rate was relatively low (18.7%), and was strongly associated with being female (92%). The lifetime comorbidity between anxiety and other mental disorders (primarily MDD) was substantial (73.1%) and was not associated with being female.