Historically, cognitive-developmental and behavior-analytic approaches to the study of human behavior change and development have been presented as incompatible alternative theoretical and methodological perspectives. This presumed incompatibility has been understood as arising from divergent sets of metatheoretical assumptions that take the form of ontological and epistemological principles, and constitute worldviews. Classically, cognitive-developmental approaches have been cast as deriving from an organismic worldview and behavior-analytic approaches from a contextualist worldview. Previous attempts at uniting the two approaches have entailed privileging one and radically modifying the other. The present paper argues that a meaningful integration requires a set of metatheoretical assumptions that transcends both worldviews, and, while maintaining their distinct qualities, unites them. This metatheoretical framework termed relational metatheory is described and its integrative implications explained.