The willingness of public authority to delegate social and environmental regulation to the private sector has varied from sector to sector, but has often led to the establishment of ‘voluntary’ standards and certifications on sustainability. Many of these have taken the form of ‘stewardship councils’ and ‘sustainability roundtables’ and have been designed around a set of institutional features seeking to establish legitimacy, fend off possible criticism, and ‘sell’ certifications to potential users. The concept of ‘roundtabling’ emphasizes the fitting a variety of commodity-specific sustainability situations into a form that not only ‘hears more voices’ (as in ‘multi-stakeholder’), but also portrays to give them equal standing at the table of negotiations (roundtable), thus raising higher expectations on accountability, transparency and inclusiveness. In this article, I examine to what extent these expectations are being met through the comparative case study of two sustainability certifications in the biofuel industry – in the context of a wider set of experiences in the agro-food and forestry sectors. I show that ‘roundtabling’ entails an ever more complex web of governance systems and procedures to meet ‘good practice’ in standard setting and management. This is opening space for competing initiatives that are less democratic, quicker, and more aligned with industry interests to establish substantial presence in the market for sustainability certifications. These tend to more easily discriminate on the basis of size (against small players) and geography (against actors in the South). The article concludes with a reflection on what can be done, through appropriate regulation, to address this situation.