In the context of calls for more effective processes to facilitate deliberative democracy in cities, and the connection often asserted between participatory means and sustainability ends in urban governance, this article examines a case of public participation for sustainability indicator selection in Vancouver, Canada. Sustainability indicator systems are often introduced via participatory exercises, but the quality of this participation and its outcomes are questionable. Based upon current debates in deliberative democratic theory, our judgment of the quality of a particular process depends on the level and mode of interaction. Do we expect, along with Healey, that participants build a rational consensus beginning from root values and visions, or do we expect, along with Mouffe, a conflictual consensus among participants working from incommensurably diverse life worlds? An examination of governmentality theory, based on the work of Rydin, adds to this a way of understanding the impact on participation outcomes of what participants learn about their own and others’ roles in democratic urban governance as they prepare recommendations specific to local sustainability. This case study analysis reflects on these theoretical debates in terms of the unfolding of a public participation process for sustainability indicator selection. It offers lessons for public process design that is better aligned with the expectations of radicalized communicative rationality and for the specific learning values of engagement for participants, which were at least as strongly related to democratic practice as they were to sustainability per se.