Deliberative democracy appears to be having a profound influence on contemporary green political theory. This article initially explores the growing fascination with democratic deliberation before raising the question of the implications for the shape of political institutions. Although both green and deliberative literatures are heavily committed to enhanced citizen participation, neither has systematically engaged with the task of institutional design. Three possible 'models' of deliberative institutions are analysed: mediation, citizen forums and referendum and initiative. Such institutional forms could be more extensively employed whether as part of a green politics of reform or as the basis for political institutions of a more radical sustainable society.