For better or worse, products contribute to shaping the behaviour of their users. Hence, designers have the opportunity, or if you are so inclined the responsibility, to take those potential behaviour changes into account in their design process. Through thoughtful design, they may aim to change user behaviour for the better and make it, for instance, more sustainable. Such design, aimed at enabling, inducing or even forcing users to behave in a more sustainable manner, is the topic of this special issue. It deals with the intersection between the disciplines of design, behaviour and sustainability. This intersection constitutes a research area that has grown considerably in recent years especially amongst design researchers (e.g., Lilley, 2009, Lockton et al., 2008, 2010). Although aspects of it have been covered in the extant literature earlier, the specific combination of the three aspects design, sustainability and behaviour, in combination with the researchers coming from a design background, is relatively new. This special issue is based on papers presented in a special session during the 14th European Roundtable on Sustainable Consumption and Production (ERSCP) Conference, which was held in Delft, the Netherlands, in October 2010. In this editorial, these papers will be put in a wider context to illustrate how they relate to each other, as well as to other recent publications in this emerging field of research.