Major strides have been made in the field of youth development. However, youth transitioning into adulthood have not received similar attention. These older youth have frequently been overlooked by policymakers and practitioners who have been more focused on designing programs and services for adolescents and young children. Because older youth face a unique set of challenges and risks as they move into adulthood, it is important to identify intervention strategies that can enhance the development and success of these individuals in domains such as employment, independent living, drug and alcohol use, pregnancy, parenting, life skills, mental health, release from the foster care system, homelessness, violence, education, and literacy. This synthesis examines the role that programs designed to serve older youth can play in promoting positive development and subsequent self-sufficiency in adulthood. The authors synthesize the findings from 31 studies that implemented random assignment intent-to-treat experimental evaluations to examine the impacts of various intervention strategies on youth well-being outcomes during the transition to adulthood (ages 18 to 25). While all programs evaluated outcomes for these "emerging adults," programs varied in the ages of targeted youth: 10 programs targeted youth from as early as 12 years and into their early twenties; eight programs served youth from 16 years and into their early twenties; and 11 programs began at 18 years of age. This review of experimental evaluations indicates that education and career programs can be effective, especially for low income youth and for youth targeted from younger ages, for example, those under age 18. Furthermore, specific intervention strategies, such as mentoring, case management, and providing child care for young parents, are associated with program success across outcomes. However, existing substance use and reproductive health programs have not consistently been found to be effective across outcomes for this age group. (Contains 1 footnote and 11 endnotes.) [Additional support for this document was provided by The Stewart Trust.]