When the term ‘actor-network theory’ or ANT is raised, probably the most immediate thought conjured up is that ANT proposes material ‘things’ have agency like human actors. As this chapter will explore, this is not exactly what ANT in any of its varieties proposes, nor is it a sufficient account of what theoretical perspectives drawing on ANT can offer planning analysts. This chapter will set out the origins and development of ANT thinking, explain the key concepts and discuss the mode of argumentation and research implied by adopting an ANT perspective. It will consider some of the key criticisms made of ANT – including those relating to the above-mentioned agency of things – and consider some responses. It concludes by outlining some possible trajectories for ANT research within planning studies.