To understand the variables responsible for the development of anxiety disorders, this chapter reviews data on the influence of both the individual's familial and social environments. Considerably more attention is paid in the literature to understanding the familial rather than the nonfamilial (i.e., social)environment. Nevertheless, data are identified that address the influence not only of parents but also of partners, siblings, peers, and culture. Empirical evidence regarding family and social relationships and treatment outcome for individuals with anxiety disorders is reviewed. Finally, the chapter examines evidence regarding the value of involving the family in the treatment of anxiety disorders.