Since passage of the Education of All Handicapped Children Act in 1975, professionals and parents have disagreed concerning how to define and implement the related services requirement of the law. Some states have enacted statutes or regulations establishing eligibility criteria; however, many have not. Although a number of due process and court cases have been filed concerning related services as a necessary component of a free and public education to students with disabilities, the narrow and sometimes conflicting outcomes of those cases has failed to provide clear guidance for the field. This article will review the Individuals with Disabilities Education Act definitions of related services, overview types of related services commonly provided in schools, and review legal decisions concerning related services and the research providing support for best practices.