This is a guide about treatment for opioid dependence from people who have lived it. The OAT Client Guide consists of a technical briefing on opioid dependence, OAT medication and the process of OAT assessment, treatment initiation, dispensing, supervision and review. It also includes standards in meaningful participation and client-centred care. The document further includes a troubleshooting section that helps address key problems that may arise in delivering an OAT care plan. With this project, EuroNPUD sought to empower people with opioid dependence to raise their knowledge about the treatment system,treatment options and the rights of people in drug treatment. This supports peers to talk in an informed and educated way when advocating for their rights.