The Interstate Wire Act of 1961, often called the Federal Wire Act, is a United States federal law prohibiting the operation of certain types of betting businesses in the United States. It begins with the text:

Whoever being engaged in the business of betting or wagering knowingly uses a wire communication facility for the transmission in interstate or foreign commerce of bets or wagers or information assisting in the placing of bets or wagers on any sporting event or contest, or for the transmission of a wire communication which entitles the recipient to receive money or credit as a result of bets or wagers, or for information assisting in the placing of bets or wagers, shall be fined under this title or imprisoned not more than two years, or both.

Several legal opinions and rulings have discussed whether forms of gambling other than sports betting fall within the Act's scope.

It is quite evident that modern, organized, commercial gambling operations are so completely intertwined with the Nation's communications systems that denial of their use to the gambling fraternity would be a mortal blow to their operations

After being selected to become U.S. Attorney General, Robert F. Kennedy suggested to the 87th United States Congress to pass legislation which would make interstate gambling illegal. Kennedy's goal of the legislation was to help the United States Justice Department stop organized crime from trafficking. One of the eight bills given to Congress was Senate Bill 1656—The Wire Act.

The Interstate Anti-Crime Acts were signed by the 35th President of the United States John F. Kennedy on September 13, 1961.

Legal opinions have varied as to whether the Wire Act applies only to sports betting, or applies to all forms of gambling, such as lotteries and casino games.

In a 2002 letter to Nevada state officials, the U.S. Department of Justice (DOJ) stated its opinion that the Wire Act "prohibits gambling over the Internet, including casino-style gambling."