The 1940 NCAA basketball tournament involved eight schools playing in single-elimination play to determine the participating champion of men's NCAA Division I college basketball. The second edition of the tournament began on March 20, 1940, and ended with the championship game on March 30 in Kansas City, Missouri. A total of eight games were played, including a single third place game in the West region.

Indiana, coached by Branch McCracken, won the tournament title with a 60–42 victory in the final game over Kansas, coached by Phog Allen. Marvin Huffman of Indiana was named the tournament's Most Outstanding Player.

This would be the only tournament to feature Springfield College, the school James Naismith worked for when he invented the sport of basketball. They were the first of fourteen colleges and universities to compete in the tournament that are no longer in Division I. This was also the first appearance of the Kansas Jayhawks, whose first coach was Naismith.

The following are the sites selected to host each round of the 1940 tournament:

March 20 and 21

East Regional, Butler Fieldhouse, Indianapolis, Indiana (Host: Butler University)

West Regional, Municipal Auditorium, Kansas City, Missouri (Host: Missouri Valley Conference)

March 30

Municipal Auditorium, Kansas City, Missouri (Host: Missouri Valley Conference)

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• 1940 National Invitation Tournament
• 1940 NAIA Division I men's basketball tournament