This article focuses on the interplay of research and practice (research. practice integration) in advancing international efforts to understand and enhance positive youth development (PYD). We discuss 3 facets of PYD research and application that have cross-cutting relevance to theory, to the use of theory for designing principles of PYD programs, and to evaluating whether specific instances of youth development programs have features that promote PYD. Using dynamic, relational developmental-systems-based concepts, we discuss the process of development involved in PYD, the use of the specificity principle to frame research and practice and, as a sample case illustrating how PYD research and practice can be advanced through the use of the specificity principle, we focus on one facet of PYD, that is, positive character, or character virtues. We point to important future directions for further illuminating the specificity of PYD process through assessing the developmental neurobiology of PYD, and we emphasize the important contributions that PYD research and practice integration can make worldwide to enhancing youth contributions to equity, social justice, and democracy.