NCAA Division I men's basketball tournament

The NCAA Division I men's basketball tournament, branded as March Madness, or The Big Dance, is a single-elimination tournament played in the United States to determine the men's college basketball national champion of the Division I level in the National Collegiate Athletic Association (NCAA). Played mostly during March, the tournament was first conducted in 1939 and currently consists of 68 teams. Known for its upsets of favored teams with its single game single-elimination format, it has become one of the greatest annual sporting events in the US.

The 68-team format was adopted in 2011; the tournament format had remained largely unchanged since 1985, when it expanded to 64 teams. Before then, the size of the field varied from as little as 8 teams to as many as 53. The field was restricted to conference champions until at-large bids were extended in 1975 and teams were not fully seeded until 1979. In 2020, the tournament was cancelled for the first time due to the COVID-19 pandemic and in the next season, the tournament was contested completely in the state of Indiana as a precaution.

37 different schools have won the tournament to date. UCLA has the most with 11 championships and their coach John Wooden has the most titles of any coach with 10. The University of Kentucky (UK) has eight championships, the University of Connecticut (UConn) and the University of North Carolina have six championships, Duke University and Indiana University have five championships, the University of Kansas (KU) has four championships and the University of Florida and Villanova University have three titles. Six programs are tied with two national championships and 22 teams have won it once.

All tournament games are broadcast by CBS, TBS, TNT and truTV under the program name NCAA March Madness. With a contract through 2032, Paramount Skydance and Warner Bros. Discovery pay $891 million annually for the broadcast rights. The NCAA distributes revenue to participating teams based on how far they advance, which provides significant funding for college athletics. The tournament has become part of American popular culture through bracket contests that award money and other prizes for correctly predicting the outcomes of the most games. In 2023, Sports Illustrated reported that an estimated 60 to 100 million brackets are filled out each year.