This special issue of Diabetic Medicine is dedicated to psychosocial research in diabetes, celebrating 25 years of the Psychosocial Aspects of Diabetes (PSAD) Study Group of the European Association for the Study of Diabetes (EASD). It includes 14 papers providing an overview of the broad scope and depth of behavioural and psychosocial research over the past quarter of a century. Three of these papers will be presented during the Diabetic Medicine symposium at this year’s Diabetes UK Professional Conference in Glasgow on 20 March 1-3.