For more than 20 years, sustainable development has been advocated as a way of tackling growing global environmental and social problems. The sustainable development discourse has always had a strong technological component and the literature boasts an enormous amount of debate on which technologies should be developed and employed and how this can most efficiently be done. The mainstream discourse in sustainable development argues for an eco-efficiency approach in which a technology push strategy boosts efficiency levels by a factor 10 (...) and more in industrialised and developing countries. A minority argues for a socio-cultural lifestyle switch, relying on new values, quality of life, sufficiency and redistribution strategies, with calls for appropriate and soft technologies. It is remarkable, however, that the articles, books and policy debates on sustainability seldom explicitly draw in a discussion of the nature of technology, how technology influences and is influenced by society, and what this implies for sustainable development. The mainstream interprets technology as neutral and instrumental: technology is no more than an instrument to reach a goal; it cannot be judged on its intrinsic characteristics, only on its use. The alternative view often builds on an autonomous and substantive interpretation of technology: technology is an autonomous, almost uncontrollable power that fundamentally reshapes our culture. A more balanced approach seems to be growing in the research on socio-technical sustainability transitions where the focus shifts to the co-evolution of technology and society, and to the networks, seamless webs and complex multi-actor processes that may carry a sustainability transition forward. This approach builds on insights from recent traditions in the philosophy and sociology of technology, in particular the social construction of technology (SCOT) and actor-network theory (ANT). While this provides for a better understanding of the nature and potential role of technology in sustainability policies, it remains to be seen whether it will actually influence the choice between technologies. This article investigates the different conceptualisations of technology in the sustainability debate. It first distinguishes between different approaches of sustainability and how these are related to differing views on technology. It then moves on to how the socio-technical transitions research incorporates insights from contemporary philosophy and sociology of technology. It reflects on the potential of transitions research to give guidance in technology choices, suggesting that the transition approach might be strengthened by drawing in insights from critical theory of technology and by taking a more political stance in defining sustainable development. (shrink)