This toolkit was developed to help program implementers, particularly Community-Based Organisations (CBOs) and others working in direct service delivery, to more effectively address safety and security challenges within their implementation of HIV programs for and with key populations. It is designed for use in hostile environments; for example, where members of key populations are criminalized and face elevated levels of stigma, discrimination, and violence. It seeks to amplify good programming through identifying and cataloging promising practices and tools, making overarching recommendations to address safety and security challenges, and providing a systematic approach (via checklists) to identify and respond to one’s own safety and security gaps. It also clearly describes the context in which safety and security investments are needed and the importance of these investments for an effective HIV response.