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 December 25, 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. 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. 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.
A revised 66-game regular season began on December 25, 2011, with five Christmas Day games, two more than the original schedule. 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. 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. 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. 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. Before that, the last occurrence was two decades earlier. On 29 occasions during the season, teams played a stretch of five games in six days. 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. 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"