The Vault™ series of survival shelters is a type of hardened subterranean installation designed by Vault-Tec Corporation on contract with the U.S. government to supposedly protect a selected fragment of the United States population from nuclear holocaust so that America could be repopulated. However, outside a minority of control Vaults, the main purpose of the Vaults were to experiment on the American population in order to conduct scientific research.

Although the term vault has many meanings, including a bank vault, it was trademarked by Vault-Tec to refer to their particular brand of shelter and thus capitalized.