An effective programme of alcohol and drug education needs to be tailored to meet pupils’ requirements and priorities, meaning that both pupils’ needs and learning processes must be regularly assessed. This paper outlines the different and complementary ways to make an assessment, exploring the following questions: Where should teachers begin? What is needs assessment within alcohol and drug education? How can needs assessment inform alcohol and drug education programme planning? This briefing paper is part of a series produced by Mentor ADEPIS on alcohol and drug education and prevention, for teachers and practitioners.