Practitioners and policymakers are beginning to design justice responses specifically for emerging adults (a life stage occurring roughly from ages 18 to 26). But community-based approaches to help young people avoid involvement with the justice system in the first place, or help them succeed afterwards, are less common. In this guide, we describe community-based strategies for supporting emerging adults in their transition to adulthood and preventing justice system contact. The guide highlights examples of innovative programs to assist young adults in three main areas: relationships and support networks, health and well-being, and stability and financial security. Efforts to support young adults can not only promote their safety and well-being, but can also advance public safety and mitigate barriers to equity.