In the United States, Who Wants to Be a Millionaire (also known simply as Millionaire) is a television reality/game show which offers a maximum prize of $1,000,000 (originally lump sum; now annuitized) for correctly answering 15 successive multiple-choice questions of increasing difficulty. The show is based on and follows the same general format of the original version of the show from the United Kingdom, and is now part of the international Who Wants to Be a Millionaire? franchise.

Who Wants to Be a Millionaire debuted in the United States on August 16, 1999 on the ABC television network, and was hosted by television personality Regis Philbin. In its initial run, it had the question mark at the end of the title just like its British counterpart. When it returned for its second run, the question mark was removed from the title.