The 2011 NCAA Men's Division I Basketball Tournament was a single-elimination tournament involving 68 teams to determine the national champion of the 2010–11 NCAA Division I men's basketball season. The 73rd edition of the NCAA Tournament began on March 15, 2011, and concluded with the championship game on April 4 at Reliant Stadium in Houston, Texas. This tournament marked the introduction of the "First Four" round and an expansion of the field of participants from 65 teams to 68. The "South" and "Midwest" regional games were replaced by the monikers "Southeast" and "Southwest" for this tournament, due to the geographical location of New Orleans and San Antonio, respectively.
The Final Four featured no top seeds for the first time since 2006, with the highest remaining seed being West Region winner, #3 Connecticut. For the first time since 2000, a #8 seed advanced to the Final Four as Butler, the national runner-up from the year before, won the Southeast Region. For only the third time ever, a #11 seed advanced to the Final Four as Virginia Commonwealth, one of the "First Four" teams, won the Southwest Region. Those three teams were joined by East Region champion Kentucky, a #4 seed.
Connecticut won its third national championship in the championship game by defeating Butler 53-41.
Upsets ruled the 2011 tournament. The East Region saw its #11 seed, Marquette, advance to the Sweet Sixteen where they were downed by North Carolina. The Southwest Region saw four of its double digit seeds win, as VCU was joined by #12 seed and citymate Richmond, #10 seed Florida State, and #13 seed Morehead State as first round winners. Florida State, VCU, and Richmond all advanced to the Sweet Sixteen from that region, and VCU defeated top-seeded Kansas in the final. Butler and #11 seed Gonzaga advanced from the Southeast Region, with Gonzaga losing in the Round of 32 to BYU.
For the third time in as many tournaments, Vanderbilt suffered a defeat to a double digit seed. This time, they were defeated by Richmond as a #5 seed.
The Big East had a record eleven teams make the tournament. Due to having more than eight teams qualify, it was possible for intra-Big East matchups to occur in the third round. Two of these matchups did occur as Marquette defeated Syracuse in the East while Connecticut defeated Cincinnati in the West. The other Big East teams to qualify were Pittsburgh, who earned the #1 seed in the Southeast Region and were knocked out in the third round by Butler, St. John's, who were the Southeast's #6 seed and were eliminated in their first game by Gonzaga, Louisville, which earned the #4 seed in the Southwest and fell to Morehead State in their first game, Georgetown, who lost to VCU in the first round as a #6 in the Southwest, Notre Dame, the #2 seed in the Southwest who were eliminated by Florida State, Villanova, who were eliminated in an #8 vs #9 matchup against George Mason in the East Region, and West Virginia, the East's #5 seed who lost in the third round to Kentucky.
Northern Colorado, winners of the Big Sky Conference, made its first NCAA Division I tournament.