The environmental impact of the fashion and textile industry (FTI) is measured and communicated through several interrelated methods, tools and platforms. In this paper, scholarly and grey literature have informed the mapping of the sector’s environmental impact assessment (EIA) landscape to identify key gaps and challenges in effectively quantifying and communicating environmental product performance. These preliminary insights informed the design of multiple focus group discussions where the on-the-ground challenges of EIA implementation were discussed with 85 FTI stakeholders, including industry professionals, academics, non-governmental organisations and local government. Key findings highlight the need for further refinement and harmonisation of assessment methodologies and approaches such as Life Cycle Analysis (LCA) to consider a wider range of impact categories to increase the comparability of results. Similarly, the communication asymmetries linked to a profusion of eco-labelling and ranking systems necessitates the development of better tools to communicate the environmental performance for the sector. Furthermore, as all EIA methods require the movement of data between various actors, there is a need for improvement and innovation in data-gathering and management systems to ensure greater quality and reliability.