The article first identifies and discusses the foundations of effective gang prevention. One foundation is an understanding of normal adolescent development which can involve risks for gang participation. The features of normal adolescent development include an orientation toward peer-related acceptance and social interaction, as well as egocentrism, which focuses on one's own emotional and social needs. Another important foundation of effective gang prevention is an understanding of why youths join gangs. This includes the factors of respect among peers, excitement, social opportunities, protection, and money. The next major section of the article provides an overview of community-based anti-gang initiatives. The author advises that the best anti-gang initiatives are tailored to meet local needs and challenges, with attention to what can be learned from broader-based research and best practices. On the front end of these initiatives are concerted efforts to understand how local gang characteristics and dynamics interact with a range of social forces that are also local and community-based. The article further advises that gang intervention includes a balance of services and opportunities for at-risk youth, combined with supervision and accountability. In addition, effective gang intervention requires coordinated partnerships among agencies and service providers, including the police, juvenile courts, schools, prosecution, and community service agencies. Such partnerships facilitate targeting and conducting outreach and services for gang-involved youth and their families. Any intervention should include graduated sanctions and effective case management. The basic framework for implementing multiple anti-gang strategies involves the combining of four strategies: enforcement, intervention, secondary prevention (targeting known gang members), and primary prevention (broad-based initiatives that aim to exert a positive influence on all youth in the community).