Prevention strategies based on scientific evidence working with families, schools, and communities can ensure that children and youth, especially the most marginalized and poor, grow and stay healthy and safe into adulthood and old age. For every dollar spent on prevention, at least ten can be saved in future health, social and crime costs. These global International Standards summarize the currently available scientific evidence, describing interventions and policies that have been found to result in positive prevention outcomes and their characteristics. Concurrently, the global International Standards identify the major components and features of an effective national drug prevention system. It is our hope that the International Standards will assist policy makers worldwide to develop programmes, policies and systems that are a truly effective investment in the future of children, youth, families and communities. This work builds on and recognizes the work of many other organizations (e.g. EMCDDA, CCSA, CICAD, Mentor, NIDA, WHO) which have previously developed standards and guidelines on various aspects of drug prevention.