Theory of Change in tourism is about understanding why and how change happens, so that development programs can make the most of the development potential of this sector. It is critically important that there is full understanding of the challenges, assumptions, solutions and indicators for tourism. The evidence behind tourism as a positive development change agent also needs to be regularly challenged and examined. To be successful, projects need to take the entire tourism landscape into consideration and leverage insights from past projects. Theory of Change (ToC) provides a framework for the planning, execution and evaluation of tourism projects and programs that connects to project goals and development objectives and helps maximize tourism's potential. This report explains Finance, Competitiveness and Innovation (FCI) Global Practice's Tourism ToC. It is written for World Bank Group Task Team Leaders (TTLs), Project Teams, and Tourism Specialists, as part of a suite of tools to help improve tourism project design. The report articulates the 'why' and 'how' of FCI's approach to project design and implementation. It includes a step-by-step guide to using Theory of Change for tourism project and program design.