The need for more dementia friendly design in hospitals and other care settings is now widely acknowledged. Working with 26 NHS Trusts in England as part of a Department of Health commissioned programme, The King’s Fund developed a set of overarching design principles and an environmental assessment tool for hospital wards in 2012. Following requests from other sectors, additional tools were developed for hospitals, care homes, health centres and housing with care. The tools have proven to be effective in both disseminating the principles of dementia friendly design and in enabling the case to be made for improvements that have a positive effect on patient outcomes and staff morale. This paper reports on the development, use and review of the environmental assessment tools, including further work that is now being taken forward by The Association for Dementia Studies, University of Worcester.