Jack in the Box is an American fast-food restaurant founded by Robert O. Peterson in 1951 in San Diego, California, where it is still headquartered today. In total, the chain has 2,200 locations, primarily serving the West Coast of the United States. Food items include the Jumbo Jack, Potato Wedges, and Ultimate Cheeseburger. The company also operates the Qdoba Mexican Grill chain.

A jack-in-the-box is a children's toy that outwardly consists of a box with a crank. When the crank is turned, it plays a melody, often "Pop Goes the Weasel". At the end of the tune there is a "", the lid pops open and a figure, usually a clown or jester, pops out of the box. Some jack-in-the-boxes open at random times when cranked, making the startle even more effective.