Vault Boy is the mascot of the Fallout media franchise. Created by staff at Interplay Entertainment, the original owners of the Fallout intellectual property, Vault Boy was introduced in 1997's Fallout as an advertising character representing Vault-Tec, a fictional megacorporation that built a series of specialized fallout shelters throughout the United States prior to the nuclear holocaust that sets up the world state of the Fallout universe.

This is one of several characters that have been tikified by Geekitikis and released as mugs, including Vault Boy, Dog Meat, Power Armor, Power Armor 2.0, and Deathclaw.