This chapter examines the distorting and negative sustainability, economic and social impacts of the pro-growth bias within conventional planning thinking and practice and suggests an outline for a post-growth planning system. It outlines what is meant by ‘economic growth’ and identifies some of the main ‘pro-growth’ biases (and carbon energy dependence) within dominant understandings of planning. These include, inter alia, planning’s role in promoting policies and discourses of international competitiveness, the privatisation of public space, support for pro-market urban regeneration and a view of planning as facilitating market-based economic growth. It then proceeds to discuss some features of ‘post-growth’ and ‘post-carbon’ planning. These include the central role of planning in any ‘just transition’ to a low carbon economy; the place of a more proactive state in that planning process, and the integration of social justice ‘floors’ and ecological ‘ceilings’ into any post-carbon, post-growth planning. The chapter concludes that we need new imaginaries and objectives for planning in the 21st century, for conditions very different from those of post-war and late 20th century.