Nationalization (British English spelling nationalisation) is the process of taking an industry or assets into government ownership by a national government or state. Nationalization usually refers to private assets, but may also mean assets owned by lower levels of government, such as municipalities, being transferred to the public sector to be operated and owned by the state. The opposite of nationalization is usually privatization or de-nationalization, but may also be municipalization.

A renationalization occurs when state-owned assets are privatized and later nationalized again, often when a different political party or faction is in power. A renationalization process may also be called reverse privatization. Nationalization has been used to refer to either direct state-ownership and management of an enterprise or to a government acquiring a large controlling share of a nominally private, publicly listed corporation.^{[citation needed]}

Nationalization was one of the major strategies advocated by socialists for transitioning from capitalism to socialism. Socialist ideologies that favor nationalization are typically called state socialism. In this context, the goals of nationalization were to dispossess large capitalists and redirect the profits of industry to the public purse, as a precursor to the long-term goals of establishing worker-management and reorganizing production toward use.