Within Social Protection programmes, M&E is often treated as a theoretical box-ticking exercise – sometimes obstacle and feared – rather than as a useful programme improvement and accountability tool. Drawing on experiences from four different country settings (Ghana, Kenya, Mozambique and Moldova), this Paper outlines a Conceptual Framework for building an effective M&E system. We show that, to be ‘fit-for-purpose’ – essentially to provide systematic and continuous information for internal improvement and external accountability – an M&E system needs to incorporate both supply- and demand-side considerations. Providing practical examples, we discuss the key factors that play a role in successfully introducing and embedding M&E practice at the macro, meso and micro level once an M&E system’s indicators, data sources and institutional framework have been adequately defined.