The chapter aims to review the changes in the structure of aid delivery over the period since 2000. A significant part of the discussion is based on statistics which illustrate many of these changes in terms of the various sources of aid (OECD DAC countries, non-DAC countries, multilateral agencies and private donors). The main data sources are the OECD QWIDS webpage (OECD 2024b) and the World Bank’s World Development Indicators (World Bank 2024). It also discusses changes in the allocation of ODA (Official Development Assistance) between directly productive, economic infrastructure, social infrastructure, humanitarian, security and ‘emergency’ sectors over these years. A distinction is made between different categories of ‘development finance’ including ODA, Official Development Finance (ODF), Other Official Finance (OOF) and lending on more commercial terms. The term ‘emerging donors’ is discussed, and the various dimensions of these donors are explored. The changing institutional complexity of the ‘aid sector’ is described together with the changing priorities and objectives of ‘traditional donors’. In part, the changing structure and priorities of the aid sector reflect international socio-economic events including natural and man-made disasters, international migration of various types and changing perceptions of how aid ‘works’. The debate relating to ‘aid effectiveness’ is reviewed critically.