The 2011–12 NBA season was the 66th season of the National Basketball Association (NBA), which began with the signing of a new collective bargaining agreement (CBA) between the owners of the 30 NBA teams and the NBA's players. The previous CBA, which was ratified in 2005, expired at 12:01 am EDT on July 1, 2011, resulting in a lockout. With the new deal in place, the regular season was shortened from the normal 82 games per team to 66, because of nearly two months of inactivity. This was the league's first season since 1991–92 without Shaquille O'Neal, who announced his retirement on June 1, 2011, via social media. A 4-time champion, O'Neal played 19 years for the Orlando Magic, Los Angeles Lakers, Miami Heat, Phoenix Suns, Cleveland Cavaliers, and Boston Celtics. The season began on Christmas Day 2011, and ended on April 26, 2012. The playoffs started on April 28 and ended on June 21 when the Miami Heat defeated the Oklahoma City Thunder in Game 5 of their series, 121–106, winning the Finals, 4–1 and to capture the franchise's second NBA title. LeBron James was named both the season MVP and the NBA Finals MVP. The NBA regular season would not begin again in December until the 2020–21 NBA season.

The lockout was the fourth work stoppage in the history of the NBA. It began at UTC (12:01 am EDT) on July 1, 2011. The main issues dividing the owners and the players were revenue sharing and the structure of the salary cap. During the lockout, teams could not trade, sign or contact players and players couldn't access NBA team facilities, trainers, or staff members. All preseason games (scheduled to begin October 9) and the first six weeks of the regular season (scheduled to begin November 1, through December 15) were canceled.^[19][20] Some players signed contracts to play in other countries, and most had the option to return to the NBA as soon as the lockout ended. On November 26, 2011, after 15 hours of talks, a tentative deal was reached; once officially ratified, the NBA started a revised 2011–12 season.^[1] Owners allowed players to have voluntary workouts at team sites starting December 1. On December 8, 2011, the lockout ended when the owners and players ratified a new CBA agreement.^[21]

Training camp began on December 9. A revised two-game preseason schedule took place.^[22]

A revised 66-game regular season began on December 25, 2011, with five Christmas Day games, two more than the original schedule.^[23] The league built a new schedule from scratch based on available arena dates. In October, the league allowed arenas in Los Angeles and Chicago to reassign NBA dates for other events. The number of games between conferences was affected as was the case in the 1999 lockout, when each team played only five or six interconference games in a 50-game schedule. Normally, each team plays teams in the other conference twice each.^[24] Teams played 48 conference games and 18 non-conference games in a 66-game schedule, compared to 52 conference games and 30 non-conference games in a normal 82-game season.^[25] Teams played on average two more games per month and also were required to play three-consecutive games at least once in the season. In total, the league had 42 sets of back-to-back-to-back games throughout the season, with 11 teams playing two such sets. The exception was the then champion Dallas Mavericks, who never had a set of 3 consecutive back to backs.^[26][27][28] The three-game set, or "triple", also occurred during the shortened 1998–99 season, which featured 64 triples and sloppier play due to tired players.^[26][27] Before that, the last occurrence was two decades earlier.^[27] On 29 occasions during the season, teams played a stretch of five games in six days.^[28] With fewer off days during the season, the level of play was lower due to fatigue, and some older players rested to avoid burnout and recuperate from injuries.^[29] When the San Antonio Spurs rested Tim Duncan for a game in March at the end of a back-to-back-to-back, coach Gregg Popovich submitted the description of Duncan's injury as "Old".^[30]

The 2012 NBA playoffs began on April 28, and concluded on June 21, 2012, when the Miami Heat defeated the Oklahoma City Thunder.

The Chicago Bulls were eliminated after losing Derrick Rose and Joakim Noah to injuries, and the New York Knicks lost to the Miami Heat while losing Baron Davis and Iman Shumpert to knee injuries. The Heat were not immune, losing Chris Bosh for most of the playoffs en route to their championship. Commissioner David Stern initially said there was no connection between the injuries and the 66-game schedule compressed into 124 days; however, he backed off those comments a week later, saying more research was needed.

This season also marked the final time that Kobe Bryant appeared in the playoffs, as an Achilles injury the following season prevented him from joining the Lakers for the 2013 first round.

^[31][32]

• On December 8, 2011, the New Orleans Hornets, the Los Angeles Lakers and the Houston Rockets agreed to a trade that would send Chris Paul to Los Angeles. NBA commissioner David Stern nullified the trade, saying the Hornets were better off keeping Paul than accepting the terms of the deal. The league had acquired the Hornets from former owner George Shinn, and the commissioner's office has final authority over all management decisions.^[33] Several of the other owners, who co-own the Hornets, also opposed the deal.^[34] Cleveland Cavaliers owner Dan Gilbert felt that the Lakers were acquiring the best player in the deal, Paul, and reducing their salary to possibly acquire Dwight Howard.^[33][35] Owners believed the trade would have sent a bad message coming out of the lockout, where one goal was to give small-market teams a chance to keep their players. Paul had long been speculated to be leaving the Hornets as a free agent after the end of the season. Magic Johnson said the trade denial "sends a bad message to fans", and Dwyane Wade called the situation a "mess".^[36] The three teams involved in the trade attempted to lobby the league to reverse its ruling^[37] as well as reconstruct the deal that would satisfy the league, only to be met by resistance from the league who wants the Hornets to receive more youth and draft picks. Later, the Lakers pulled out of the trade talk.^[38] Five days later, Paul was finally traded to the Los Angeles Clippers.^[39]
• The Toronto Raptors became the first North American sports franchise to apply 3D application to its hardwood floor, which when seen by the players and in-arena spectators appears flat, but when seen by the television audience appears popped up. It made its debut in a pre-season game against the Boston Celtics at Air Canada Centre on December 18. On December 21, when the two teams met at the TD Garden, the Celtics became the first team to apply their Twitter account on their trademark parquet floor.
• The Raptors also became the first NBA team to unveil camouflaged uniforms, which they wore for the first time on March 21 against the Chicago Bulls as a tribute to the Canadian Forces.^[40]
• Due to a career-ending knee injury, Portland Trail Blazers guard and three-time All-Star Brandon Roy announced his retirement, after only five seasons, on December 9, 2011. Roy's retirement was brief, however, as he joined the Minnesota Timberwolves the next season.
• A new shot-clock rule was put into place. Upon reaching the five-second mark, tenths of a second is displayed in order to accurately determine last-second shots.
• The Conseco Fieldhouse, the arena of the Indiana Pacers was renamed to Bankers Life Fieldhouse. On December 26, 2011, they played their first game in the newly named arena against the Detroit Pistons. Likewise the Oklahoma City Thunder's arena was renamed the Chesapeake Energy Arena, after Chesapeake Energy acquired naming rights.
• Final season of the Nets playing in New Jersey. They spent a total of 36 seasons in New Jersey in four different locations (Teaneck Armory, Piscataway's Rutgers Athletic Center, East Rutherford's Izod Center (Brendan Byrne and Continental Airlines Arena), and Newark's Prudential Center) from 1977 to 2012. They are scheduled to move to Brooklyn, a borough of New York City, the next season at the Barclays Center, becoming the first "Big Four" sports franchise in Brooklyn since the Brooklyn Dodgers left in 1957.
• All four active NBA teams formerly in the American Basketball Association (New Jersey Nets (as the New York Nets), San Antonio Spurs (as the Texas Chaparrals), Denver Nuggets, Indiana Pacers) along with the Minnesota Timberwolves (as the Minnesota Muskies), the Memphis Grizzlies (as the Memphis Tams), the Los Angeles Clippers (as the Los Angeles Stars), the Charlotte Bobcats (as the Carolina Cougars), and the Miami Heat (as the Miami Floridians) participated in NBA Hardwood Classics Nights as a tribute to the ABA wearing throwback jerseys.
• On February 19 in an overtime win vs. the Denver Nuggets, Kevin Durant scored 51, Russell Westbrook scored 40, and Serge Ibaka had a triple-double marking the first time that a player scores 50+ points, with another scoring 40+ points, and another having a triple-double in the same game.
• On March 25, the Atlanta Hawks defeat the Utah Jazz 139–133 at Philips Arena in the first quadruple-overtime game since November 14, 1997, when the Phoenix Suns defeated the Portland Trail Blazers 140–139.^[41]
• On April 13, Tom Benson, who owns the NFL's New Orleans Saints, agreed to buy the Hornets from the NBA for $338 million.
• On April 26, the New Jersey Nets played their last game against the Toronto Raptors before moving to Brooklyn, New York.
• The Charlotte Bobcats set the single–season NBA record for the worst winning percentage, going 7–59 for a .106 winning percentage. The 1972–73 Philadelphia 76ers previously held the record with .110, but they played the typical 82–game schedule.
• Kevin Durant became the seventh player to win three consecutive scoring titles, and the first since Michael Jordan notched the last scoring title of his career in the 1997–98 season.
• The Philadelphia 76ers became the fifth eighth seed to defeat a top seed in the playoffs, winning the first round series in six games over the Chicago Bulls. The Bulls lost reigning MVP Derrick Rose to an ACL injury in Game 1, who consequently missed the rest of the series.

• List of NBA regular season records