Although childhood generalized anxiety disorder is generally understudied, worry, the cardinal feature of GAD, appears to be relatively common in youth. Despite its prevalence, there are few conceptual models of the development of clinical worry in children. The current review provides a framework for integrating the developmental psychopathology perspective, models of worry in adults, and data available on worry in children. General risk factors for the development of worry are considered, as well as potential pathways including genetics, temperament, cognitive, emotional and parenting influences, as well as the influence of cognitive development. Based on this review, it appears unlikely that main effects models will be able to explain the development of GAD or clinical worry in children and that a broad, complex model incorporating a number of factors and their interactions will best describe etiological and maintaining factors. With this perspective in mind, a number of suggestions for future work are offered.