The impact of today’s fashion industry has far reaching environmental consequences. And while raw material production and end of use may spring to mind, the processing stage of the supply chain, including pretreatment, colouration (dyeing and printing) and finishing, is often overlooked as a critical area for pivotal and positive change. This guide, based on industry and Fashion for Good research, is designed to provide an overview and deeper understanding of the processing stage, including innovative technologies that would help drastically reduce the water, energy and chemistry used, as well as replacing hazardous chemistry currently used.