2005–06 NCAA Division I men's basketball season
The RCA Dome was the site of the Final Four and Championship game to end the 2005–06 season.
Preseason AP No. 1	Duke Blue Devils[1]
Regular season	November 6, 2005– March 14, 2006
NCAA Tournament	2006
Tournament dates	March 14 – April 3, 2006
National Championship	RCA Dome Indianapolis, Indiana
NCAA Champions	Florida Gators
Other champions	South Carolina (NIT)
Player of the Year (Naismith, Wooden)	JJ Redick, Duke
← 2004–05 2006–07 →

The 2005–06 NCAA Division I men's basketball season began on November 6, 2005, progressed through the regular season and conference tournaments and concluded with the 2006 NCAA Division I men's basketball tournament championship game on April 3, 2006, at the RCA Dome in Indianapolis, Indiana. The Florida Gators won their first NCAA national championship with a 73–56 victory over the UCLA Bruins. This was the last Final Four site at the RCA Dome. The Final Four will return to the city of Indianapolis, but will be held at Lucas Oil Stadium.

• Prior to the season, the NCAA purcshased the National Invitation Tournament (NIT) from the Metropolitan Intercollegiate Basketball Association (MIBA). The NCAA took over operation of the NIT beginning in 2006, and MIBA, which had owned and operated the tournament for its first 68 years,^[2] was dissolved.
• Prior to the season, a major realignment of teams in the Big East Conference and Atlantic Coast Conference (ACC) sent shock waves across college basketball:
  • Boston College, which had become a charter member of the Big East in the 1979–80 season, followed Virginia Tech and Miami (who had moved the year before) from the Big East to the ACC.
  • The Big East brought in five teams from Conference USA (C-USA) —Cincinnati, DePaul, Louisville, Marquette, and South Florida. **To replace the teams that defected to the Big East (as well as TCU, which left C-USA for the Mountain West Conference and Charlotte and Saint Louis, who left for the Atlantic 10 Conference), Conference USA brought in six new members: Rice, SMU, Tulsa, and UTEP from the Western Athletic Conference; Marshall from the Mid-American Conference, and Central Florida from the Atlantic Sun Conference.
  • The Western Athletic Conference (WAC) added New Mexico State (from the Sun Belt Conference) and Idaho and Utah State (both from the Big West Conference).
  • East Tennessee State moved from the Southern Conference to the Atlantic Sun Conference.
  • The Colonial Athletic Association added Northeastern from the America East Conference and Georgia State from the Atlantic Sun Conference.
  • Troy moved from the Atlantic Sun Conference to the Sun Belt Conference.
• The preseason AP All-American team was named on November 8. JJ Redick of Duke was the leading vote-getter (67 of 72 votes). The rest of the team included Shelden Williams of Duke (63 votes), Dee Brown of Illinois (51), Adam Morrison of Gonzaga (45) and Craig Smith of Boston College (31).^[3]
• On February 1, 2006, the Rating Percentage Index (RPI) became available to the public for the first time, appearing on the NCAA Web site.^[4]
• JJ Redick of Duke and Adam Morrison of Gonzaga engaged in a year-long battle for the national scoring title and Player of the Year honors. Morrison won the scoring race, edging Redick by 1.3 points per game. However, Redick won most National POY Awards, though in 2006 he and Morrison became the first co-winners of the Oscar Robertson Trophy.
• Paul Millsap of Louisiana Tech became the first player ever to lead the nation in rebounding for three consecutive years.^[5]
• In the 2006 NCAA tournament, George Mason made an improbable run to the Final Four, becoming the first true mid-major to do so since Penn in 1979. The Patriots' path was not easy, as they defeated schools that had won three of the past six titles—national powers Michigan State, North Carolina, and Connecticut—en route to its first Final Four berth.
• Florida won its first national title in basketball, defeating UCLA in the NCAA tournament's championship game 73–57. The team was led by a group of sophomores, several of whom were the offspring of retired professional athletes, nicknamed "The Oh-fours". Forward Al Horford and guard Taurean Green were the sons of former NBA players (Tito Horford and Sidney Green, respectively), while center and Final Four MOP Joakim Noah was the son of retired tennis pro Yannick Noah. These three (along with fellow sophomore star Corey Brewer) surprised many by choosing not to enter the 2006 NBA draft, but instead returning to try to repeat as champions in the 2006–07 season.

The top 25 from the AP and ESPN/USA Today Coaches Polls November 7, 2005.^[6]

These schools joined new conferences for the 2005–06 season.

Thirty conference seasons concluded with a single-elimination tournament. Generally, all member schools were eligible to participate in their conference tournament regardless of their records, but the Big East did not invite its teams with the worst records to its 2006 tournament. Conference tournament winners received an automatic bid to the 2006 NCAA Division I men's basketball tournament, while a school that won its conference regular season title but did not win its conference tournament was guaranteed a bid to the 2006 National Invitation Tournament unless it received an at-large bid to the NCAA tournament. The Ivy League was the only NCAA Division I conference that did not hold a conference tournament, instead sending its regular-season champion to the NCAA tournament.

Eleven schools played as Division I independents.^[80] Only IPFW, Savannah State, Texas A&M–Corpus Christi, and Texas–Pan American were considered full NCAA Division I schools, as the rest were still in a transition phase from NCAA Division II.^[80]