CRiSTAL Food Security is a decision-support tool for local-level government staff and development practitioners to support climate resilience of food systems at the community level. It aims to help users to understand the key elements of a community food system and their sensitivity to climate variability and change; the resilience of food system elements to climate variability and change, and how to improve it; and what indicators can help monitor the evolution of community food system resilience over time. CRiSTAL Food Security is mainly targeted at local-level decision-makers, such as municipal or district-level government staff, project managers of development organizations and local community leaders. The tool consists of a series of Microsoft Excel spreadsheets and produces as a main output a series of automatically generated reports based on information entered into the spreadsheets. This manual guides users through each analytical step of the CRiSTAL Food Security tool.