For many decades, participatory approaches, with their emphasis on farmer-centred management, have been presented as panaceas for overcoming weaknesses in irrigation systems. Participatory Irrigation Management (PIM) has assumed such a high status that it is regularly mandated by donors sponsoring irrigation upgrades in poor countries. However, the success of PIM is mixed, and economic analysis can help explain why PIM might work in some settings and not in others. This Special Issue focusses on PIM and aims to scrutinise its usefulness, particularly in South Asia. The focus on South Asian irrigation is driven by the reality that smallholder agriculture is destined to be the mainstay for this most populous region, at least in the medium term, and finding solutions to raise agricultural productivity is a high priority. The Special Issue comprises nine papers employing several strands of economics, including New Institutional Economics, Game Theory, and Behavioural Economics. A synopsis of each paper is provided in this editorial.