The proportion of teenagers engaging in sex has declined in recent decades, and rates of teen births in the United States have reached a historic low (Osterman et al., 2022). However, risky sexual activity, which can result in teen pregnancies and sexually transmitted infections (STIs), remains a concern. To help reduce teen pregnancies and STIs and their negative consequences, Congress authorized the Personal Responsibility Education Program (PREP). The Family and Youth Services Bureau (FYSB) within the Administration for Children and Families (ACF) of the U.S. Department of Health and Human Services (HHS) administers PREP. FYSB funds formula and competitive grants to U.S. states, territories, tribes, and local organizations to provide programming on adolescent pregnancy prevention and adulthood preparation subjects (APSs). FYSB and the Office of Planning, Research, and Evaluation within ACF contracted with Mathematica to conduct the PREP Studies of Performance Measures and Adulthood Preparation Subjects. As part of the studies, this report uses grantee-submitted data on performance measures to describe PREP programs that operated from 2017 to 2021. Specifically, this report addresses the following questions: (1) How did grantees operate and support PREP programs?; (2) What were the characteristics of PREP programs, and how did grantees and providers implement them?; (3) What were the characteristics of youth participants?; and (4) How did youth respond to the PREP programs? This report discusses trends over time for each research question. Chapter II describes the structure of the PREP grant operations, including scale, use of funds, and staffing. In Chapter III, the authors explore how grantees supported PREP program implementation. In Chapter IV, the authors discuss the characteristics of the programs, including their content, delivery, and their target populations. Chapter V describes the youth served by PREP programs, and Chapter VI explores their response to the program and their perception of program effectiveness. Finally, in Chapter VII, the authors conclude by summarizing the key findings. Through a series of callout boxes, the report spotlights how the COVID-19 pandemic impacted PREP programming and data collection.