This paper presents a model for studying ageing and technology. It investigates the theoretical gains that can be made by combining insights from Age Studies and Science and Technology Studies (STS). Although technology has become a much more salient part in the everyday lives of older people and investments are high in technologies to deal with the alleged challenges of demographic change, theory development about ageing–technology relations has not kept up with these trends. Partly this is due to the poor connection between the social scientific understanding of ageing and the technically focused discipline of gerontechnology. This has led to an interventionist logic that underlies much of the current and implicit theorising about ageing and technology. We briefly analyse the problems of the interventionist logic and then present a model that conceptualises ageing and technology as co-constituted. We propose this model – which we call the CAT-model – to highlight a number of fundamental ideas about ageing–technology relations. At the centre are four different arenas (life-worlds of older people, design worlds, technological artefacts and images of ageing) in and across which these relations can and should be studied. To develop the model, we build on our own theoretical and empirical work over the last decade, and on examples from recent scholarship that straddle the disciplinary boundaries between STS and Age Studies.