Given that prioritization of programmes is a key concern in Local Agenda 21 processes, the aim of this paper is to explore how the Analytic Network Process (ANP) can provide greater consistency and legitimacy to prioritization of local action plans. Through the analysis of an experience in the municipality of Benetusser in Spain, the study shows how ANP, by modelling reality as a network of multiple and mutual interrelations, embraces complexity and translates it into a set of operational questionnaires that help participants to reflect on their preferences and think deeply on the real implications of programmes for sustainable development. In the case study, citizens, technical staff and politicians of Benetusser carried out the prioritization process by defining a set of criteria and assessing the programmes in an interrelated way. The experience shows that the ANP procedure not only allows prioritization to be dealt with in an organized and systematic way, but also enables reflective thinking on sustainable development and the role of Local Agenda 21 itself. Copyright © 2011 John Wiley & Sons, Ltd and ERP Environment.