This article considers the context of the emerging developing country public finance and identifies two particular driving forces behind its increased complexity: the policy space between public and private within countries, and the policy space between countries and institutions in the international arena. The article highlights that international co-operation happens not as much across national borders as at a national level influenced by international agreements. Hence the building of common approaches to partnerships, prioritisation and budgeting is important for the efficient mobilisation of resources. The article also stresses the need for more direct co-operation between countries, particularly in a regional developing context; the role of ministries of finance and budget offices in ensuring the growth of such co-operation; and the need to streamline budget institutions to ensure their effectiveness.