The 1956 NCAA basketball tournament involved 25 schools playing in single-elimination play to determine the national champion of men's NCAA college basketball. It began on March 12, 1956, and ended with the championship game on March 24 on Northwestern University's campus in Evanston, Illinois. A total of 29 games were played, including a third-place game in each region and a national third-place game.

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The 1955–56 season was the last in which only one NCAA Tournament was held. Effective in 1956–57, the NCAA divided its membership into two competitive levels. The larger and more competitive athletic programs were placed in the University Division, and smaller programs in the College Division. Accordingly, that season would see separate tournaments contested in the University and College Divisions. In 1973, the University Division would be renamed NCAA Division I, while the College Division would be split into today's Divisions II and III.

This was the first NCAA tournament in which the four regionals were given distinct names, although the concept of four regional winners advancing to a single site for the "Final Four" had been introduced in 1952.

San Francisco, coached by Phil Woolpert, won the national title with an 83–71 victory in the final game over Iowa, coached by Bucky O'Connor. Hal Lear of Temple was named the tournament's Most Outstanding Player.

* – Denotes overtime period

• 1956 National Invitation Tournament
• 1956 NAIA Basketball Tournament

• Canisius's first-round victory over the second-ranked North Carolina State Wolfpack, considered by many to be among the top ten upsets in tournament history,^[1][2] set a record for most overtime periods in a Division I men's tournament game with four, a record that still stands as of 2023^[update] (tied once, in 1961).^[3]
• Northwestern University previously hosted the first ever NCAA Men's Basketball Championship game on March 27, 1939, in the first Patten Gym.^[4]
• Alabama (21-3, 14-0) had won the Southeastern Conference and had their all-time highest ranking (#4) at the end of the 1956 season, but due to a rule that players could not play as freshman, as their entire starting lineup had previously done, they were ruled ineligible for the 1956 NCAA Tournament.^[5]
• There were six new participants in the 1956 tournament: Houston, Manhattan, Marshall, Michigan State, Morehead State and Wayne University (which became Wayne State University later that year). This was the only tournament for the Tartars (now Warriors), as they would drop to the College Division and eventually Division II. They are one of five teams to win a game in the tournament and drop from what is now Division I afterwards.