This report contributes to the broader international debate on why we need multilateralism and how to make it more effective to achieve the 2030 Agenda. At a time when the value of multilateralism is being questioned, the report provides new evidence and recommendations for a new “pact” on multilateralism. This pact would be founded on recognition of the mutual responsibility of sovereign states and multilateral institutions to create a stronger, more effective multilateral system. The report offers a detailed overview of official development assistance (ODA) spending through the multilateral system. This year’s edition introduces three innovations. First, it examines the growing role of China, other sovereign states, philanthropy and the private sector as funders of multilateral organisations. Second, it analyses concessional and non-concessional spending by multilateral institutions, and discusses how multilateral action needs to adapt to the new development agenda. Third, it presents a new multi-dimensional metrics to measure the quality of multilateral funding, using financing to the World Health Organisation as a case study. Building on this evidence, the report outlines policy recommendations that provide a sound basis for principles of good multilateral donorship to deliver on the 2030 Agenda.