Youth development programs and practitioners have the potential to guide youth on a path marked by thriving. When youth develop positively and thrive, they make important and lasting contributions to their communities and to the world around them. In this chapter, we talk about theory and intentional practice in youth development programs aimed at promoting the positive development of young people. We also provide examples of how adults in such programs can help youth to develop positively and thrive. Insights from the Reconnection of the 4-H Study of Positive Youth Development as well as nascent research on the impact of youth development programs into adulthood demonstrate that such programs already have a positive impact on young adults’ outcomes, including social-emotional well-being, educational attainment, and civic engagement. The research findings and ideas presented in this chapter are intended to highlight the importance of participation and engagement in youth development programs for youth and young adults. When youth thrive, we all thrive.