There is no consensus about how to define a PPP. The term can cover hundreds of different types of long-term contracts with a wide range of risk allocations, funding arrangements, and transparency requirements. The advancement of PPPs, as a concept and a practice, is a product of the new public management of the late 20th century, the rise of neoliberalism, and globalization pressures. Despite there being no formal consensus regarding a definition, the term has been defined by major entities.

For example, The OECD formally defines public-private-partnerships as “long term contractual arrangements between the government and a private partner whereby the latter delivers and funds public services using a capital asset, sharing the associated risks”.

According to David L. Weimer and Aidan R. Vining, “A P3 typically involves a private entity financing, constructing, or managing a project in return for a promised stream of payments directly from government or indirectly from users over the projected life of the project or some other specified period of time”.

A 2013 study published in State and Local Government Review found that definitions of public-private partnerships vary widely between municipalities: “Many public and private officials tout public-private partnerships for any number of activities, when in truth the relationship is contractual, a franchise, or the load shedding of some previously public service to a private or nonprofit entity.” A more general term for such agreements is “shared service delivery”, in which public-sector entities join together with private firms or non-profit organizations to provide services to citizens.