Legislative philosophy which aims to remove previously enacted regulations on an industry in order to achieve efficiencies only possible with competition in the free market. The idea is often associated with conservatism, and is particularly popular among fiscal conservatives. The conflict with deregulation is that often industries were regulated in order to protect consumers from free market pressures, or to provide services that the market does not support.

An early example of deregulation is the airline industry, where prices were controlled by federal legislation until the early 1980s. Since deregulation, there has been an enormous drop in fares, though some people believe safety and diversity of routes have suffered. More recently, local telephone service and (in some states) the energy industry have been deregulated.