The Gender-Transformative Accelerator (GTA) tool is a self-contained, process-oriented, rapid analysis and action planning tool for implementers, advocates and technical staff working on initiatives to prevent and respond to child, early and forced marriages and unions. The tool is designed for the UNFPA-UNICEF Global Programme to End Child Marriage (the Global Programme) and is centred within the Global Programme’s definitions and core elements of gender-transformative programming, but can be applied to broader gender equality, adolescent empowerment and sexual and reproductive health programmes with minimal adaptation. This guide provides instructions on how to run a workshop on the GTA tool.