South Asia is home to nearly a quarter of the world’s population and is a region of dynamic economic growth, yet it performs relatively poorly on health and nutrition indicators. As a potential route towards addressing this poor performance, a range of accountability initiatives has been implemented to improve service delivery in the health and nutrition sectors. This is a rich and vibrant field, with a great deal to offer in terms of best practice; but there is little work that focuses on South Asian innovation and practice generally, and takes a comparative and theoretical perspective to ground existing and future accountability initiatives in health and nutrition specifically. This report fills this gap. It first summarizes current concepts and issues in accountability thinking and practice, focusing on practices commonly referred to as a ‘social accountability’. It goes on to contrast these with the ‘standard model’ of political and administrative accountability, which is prevalent in the literature, and points to ways in which reality often deviates from this standard model. Against this general conceptual and theoretical backdrop, it examines health systems in South Asia in the light of assumptions underpinning the standard model of accountability.