Lying constitutes a problematic behavior for parents and other social agents involved in children's development of effective behaviors. This analysis suggests that lying is, in part, the name for a lack of correspondence between saying and doing, and that effective correspondence training procedures can be designed to teach truthfulness in children through the teaching of either promise-then-do correspondence or do-then-report correspondence. This paper proposes a relational definition of lying and shows its applications in the area of correspondence training. The generalization and maintenance of truthfulness, advantages and disadvantages of correspondence training in the management of lying are also considered.