Schools are an important venue for implementing drug prevention programmes. School-based programmes have been shown to be an efficacious and cost-effective method of reducing substance use disorders among youth. There exists lack of consensus, however, regarding who makes the most effective programme providers. Drug prevention programmes are led by a wide variety of people, including classroom teachers, mental health professionals and the police. Few studies specifically examine the relative effectiveness of different facilitators and existing results are mixed. This has made it difficult to determine empirically which group makes the most effective programme providers. The purpose of this paper, therefore, is to present information that can be used by school officials, educators and policymakers to inform choices regarding who should implement drug prevention programmes in schools. The paper will include a brief introduction to universal classroom-based drug prevention in the USA and an overview of the role of facilitator. A discussion of the practical implications and relative (dis)advantages of using persons from three commonly used provider types (classroom teachers, mental health professionals and the police) is also provided. The paper concludes with a brief summary of programme provider issues in an international context. The information presented in this paper provides important insights for schools as they attempt to select the most appropriate programme providers for their specific communities.