Privatization (also privatisation in British English) can mean several different things, most commonly referring to moving something from the public sector into the private sector. It is also sometimes used as a synonym for deregulation when a heavily regulated private company or industry becomes less regulated. Government functions and services may also be privatised (which may also be known as "franchising" or "out-sourcing"); in this case, private entities are tasked with the implementation of government programs or performance of government services that had previously been the purview of state-run agencies. Some examples include revenue collection, law enforcement, water supply, and prison management.

Another definition is that privatization is the sale of a state-owned enterprise or municipally owned corporation to private investors; in this case shares may be traded in the public market for the first time, or for the first time since an enterprise's previous nationalization. This type of privatization can include the demutualization of a mutual organization, cooperative, or public-private partnership in order to form a joint-stock company.

Separately, privatization can refer to the purchase of all outstanding shares of a publicly-traded company by private equity investors, which is more often called "going private". Before and after this process the company is privately owned, but after the buyout its shares are withdrawn from being traded at a public stock exchange.