This article argues that a contemporary form of ‘cosmopolitan legality’ serves as an animating force behind contemporary practices of global civil society and global governance. The first part provides an account of the recent history of civil society engagement with the World Trade Organization. It observes that civil society groups have focused their collective efforts on issues relating to procedural legitimacy, including accountability, openness, and transparency, potentially to the detriment of efforts to bring about more fundamental change. In the second part of the article, various theoretical approaches to cosmopolitan legality are discussed, including their claimed Kantian origins, and are mapped on to the preceding discussion of the place of a global public sphere in global governance. Programmatic approaches that purport to mobilize cosmopolitanism in the service of either a political or legal project are ultimately rejected, and a provisional alternative reading is suggested.