This article argues that the Institute of Development Studies (IDS) has made substantial contributions to the global social protection discourse, initially through its work on vulnerability, accountability and participatory approaches, and more recently through the work of the Centre for Social Protection (CSP) on social protection as a mechanism for achieving both economic development and social justice. These contributions are discussed at the ‘ideas’ level, where IDS/CSP has contributed three influential conceptual frameworks – ‘transformative’, ‘adaptive’ and ‘inclusive’ social protection – as well as at the ‘instruments’ level, where the CSP has been< active in debates and policy processes from programme design through to impact evaluation.