Youth report that their most common sources for the alcoholic beverages they drink are individuals older than age 21. Enforcement related to these third-party transferences of alcohol warrant a high priority. There are laws, statutes, ordinances, and other enforcement tools that address third-party transferences of alcohol to underage youth. These provide the authority for criminal justice agencies to design and implement strategies that prevent and detect third-party alcohol transferences to underage youth, as well as hold accountable the responsible third parties. This guide presents an overview of related issues, enforcement techniques, and examples from communities that can be valuable resources in deterring and reducing third-party sales in a community. This guide also discusses barriers to enforcement and suggests approaches to overcoming them. In addition, strategies are suggested for working with the media to deter third-party alcohol transactions and to create and demonstrate community support. 12 references and a listing of resource web sites and other enforcement operations guides in this series