Purpose
To discuss developmental systems models of human development and explain how they offer a productive frame for research, policies, and programs aimed at understanding adolescents’ development and enhancing their health and positive development. Contemporary developmental theory stresses that the multiple levels of organization involved in human life (ranging from biology through culture, the natural and designed ecology, and history) are systemically integrated across ontogeny. Relations within this developmental system are the focus of developmental analysis and application

Methods
The key features of developmental systems theories are reviewed, and their use for framing scholarship about and applications for improving adolescent development are assessed.

Results
We demonstrate the potential of contemporary developmental theory for understanding the character and dynamics of adolescent development and for using this knowledge for the design of effective policies and programs that promote positive youth development.

Conclusions
An adequate and sufficient science of adolescent development, and one that is able to help in the development of successful policies and programs for youth, must integratively study the relations between individuals and contexts in an integrated, systemic, and temporal manner.