The 2011 NCAA Division I men's basketball tournament involved 68 teams playing in a single-elimination tournament that determined the National Collegiate Athletic Association (NCAA) Division I men's basketball national champion for the 2010-11 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. Due to the geographical location of New Orleans and San Antonio, the "South" and "Midwest" regional games were replaced by the monikers "Southeast" and "Southwest" for this tournament, 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. This was also the first Final Four to not feature any 1-seed or 2-seeds. The Final Four had the highest combined Final Four seeds since seeding started in 1979, with 26 (11-VCU, 8-Butler, 4-Kentucky & 3-Connecticut). Connecticut defeated Butler in the championship game 53–41, winning its third national championship as in many attempts.

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 appearances, 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 make the tournament (the conference then had 16 total teams). 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.

This was the last NCAA tournament until 2023 in which a mid-major conference saw multiple teams reach the Sweet 16, as both BYU and San Diego State did from the Mountain West Conference.

Northern Colorado, winners of the Big Sky Conference, made its first NCAA Division I tournament.

For the first time, a total of 68 teams entered the tournament.^[1] Thirty of the thirty-one automatic bids were given to the programs that won their conference tournaments, while the remaining automatic bid went to the Ivy League champion Princeton, as the conference does not hold a tournament. The remaining 37 teams were granted "at-large" bids, which are extended by the NCAA Selection Committee. All 68 teams were announced on "Selection Sunday" March 13, 2011.

The Selection Committee ranked the entire field from 1 to 68. The last four at-large teams selected and the four lowest ranked automatic qualifiers played in a "First Four".^[2] The four winners of those games advanced to the main draw of the tournament to play a higher seed. The four lowest ranked teams of the 68 played against each other in a pair of First Four games, with winners advancing to play No. 1 seeds, and the last four at-large teams played in the other two First Four games, with the winners moving on to face the seed they would otherwise be matched up against, as determined by their seed number.

Dayton

Tulsa

Tucson

Denver

Cleveland

Tampa

Charlotte

Chicago

Washington, D.C.

2011 First Four (orange), and first and second rounds (green)

San Antonio

Anaheim

New Orleans

Newark

Houston

2011 Regionals (blue) and Final Four (red)

The following sites were selected to host each round of the 2011 tournament:^[3][4]

First Four

• March 15 and 16
  • University of Dayton Arena, Dayton, Ohio (Host: University of Dayton)

First and Second rounds

• March 17 and 19
  • Verizon Center, Washington, D.C. (Host: Georgetown University)
  • McKale Center, Tucson, Arizona (Host: University of Arizona)
  • Pepsi Center, Denver, Colorado (Host: Mountain West Conference)
  • Tampa Bay Times Forum, Tampa, Florida (Host: University of South Florida)
• March 18 and 20
  • Quicken Loans Arena, Cleveland, Ohio (Host: Cleveland State University)
  • Time Warner Cable Arena, Charlotte, North Carolina (Host: University of North Carolina at Charlotte)
  • United Center, Chicago, Illinois (Host: Big Ten Conference)
  • BOK Center, Tulsa, Oklahoma (Host: University of Tulsa)

Regional semifinals and Finals (Sweet Sixteen and Elite Eight)

• March 24 and 26
  • West Regional
    • Honda Center, Anaheim, California (Host: Big West Conference)
  • Southeast Regional
    • New Orleans Arena, New Orleans, Louisiana (Host: Tulane University)
• March 25 and 27
  • Southwest Regional
    • Alamodome, San Antonio, Texas (Host: University of Texas at San Antonio)
  • East Regional
    • Prudential Center, Newark, New Jersey (Host: Seton Hall University)

National semifinals and championship (Final Four and championship)

• April 2 and 4
  • Reliant Stadium, Houston, Texas (Hosts: University of Houston, Rice University)

*See First Four.

Unless otherwise noted, all times listed are Eastern Daylight Time (UTC−04)

• The R32, S16, E8, F4, CG, and NC columns indicate how many teams from each conference were in the round of 32 (third round), Sweet 16, Elite Eight, Final Four, championship game, and national champion, respectively.
• The SWAC and Sun Belt Conference each had one representative, eliminated in the first round.
• The America East Conference, Atlantic Sun Conference, Big Sky Conference, Big West Conference, Ivy League, MAAC, MAC, MEAC, MVC, NEC, Patriot League, Southern Conference, Summit League, and WAC each had one representative, eliminated in the second round with a record of 0–1.
• The Big South and Southland each had one representative, eliminated in the second round with a record of 1-1.
• The Big East Conference had a record 11 teams in the tournament, which made intra-Big East matchups possible prior to the Elite Eight. There were two such matchups in the 3rd round, Syracuse vs. Marquette and Connecticut vs. Cincinnati. The two Big East teams to make the Sweet Sixteen beat conference opponents to advance to that round.

• 2011 NCAA Division II men's basketball tournament
• 2011 NCAA Division III men's basketball tournament
• 2011 NCAA Division I women's basketball tournament
• 2011 NCAA Division II women's basketball tournament
• 2011 NCAA Division III women's basketball tournament
• 2011 National Invitation Tournament
• 2011 Women's National Invitation Tournament
• 2011 NAIA Division I men's basketball tournament
• 2011 NAIA Division II men's basketball tournament
• 2011 NAIA Division I women's basketball tournament
• 2011 NAIA Division II women's basketball tournament
• 2011 College Basketball Invitational
• 2011 CollegeInsider.com Postseason Tournament