Behavior-change principles and approaches are critical to reaching the desired impact of development work. Behavior change ensures the safe, effective, and sustainable use of services provided, helping change norms that can transform communities and enable achievement of health and well-being. The purpose of this document is twofold: first, to equip World Vision staff members and development industry professionals with evidence-based knowledge and practical tools to carry out WASH behavior-change programming in communities. Second, this guide is meant to support World Vision staff across our global Partnership to communicate with knowledge and technical accuracy about behavior change in general, with a focus on WASH behavior change, and about World Vision’s approaches and capacity.