Determining the greatest upset in college basketball history often points to legendary moments in the NCAA Division I Men's Basketball Tournament. Widely cited historical shockers include Chaminade University's iconic victory over top-ranked Virginia in 1982, and UMBC becoming the first-ever 16-seed to defeat a number-one overall seed (Virginia) in 2018. These monumental upsets completely upended tournament brackets and cemented permanent legacies within the lore of March Madness.