- A new league dress code was put into effect at the beginning of the year by commissioner David Stern.
- The Miami Heat win their first NBA championship in franchise history. They become the third franchise (joining the 1969 Boston Celtics and 1977 Portland Trail Blazers, later joined by the 2016 Cleveland Cavaliers and 2021 Milwaukee Bucks) to win the NBA Finals after losing the first two games. They are also the first of the four (two?) 1988/89 expansion franchises to win a championship.
- The All-Star Game was played on February 19, 2006, at the Toyota Center in Houston with the East beating the West 122–120. LeBron James of the Cleveland Cavaliers won the game's MVP honors the youngest ever in All-Star Game history at 21 years, and 51 days old.
- This season marked the first season for the Charlotte Bobcats in their new arena in downtown Charlotte.
- Due to the damages caused by Hurricane Katrina, the New Orleans Hornets played 36 regular season games in the Ford Center in Oklahoma City, 1 game in the Lloyd Noble Center in Norman, Oklahoma, 1 game at LSU's Pete Maravich Assembly Center, and just 3 games at the New Orleans Arena in New Orleans in March. Due to the split, the team was officially referred to as the New Orleans/Oklahoma City Hornets.
- This season marked the first under the NBA's new Collective Bargaining Agreement, agreed upon by the owners and the player union on June 21.
- The season was marked by the 30th anniversary of the absorption of four American Basketball Association members into the league: The Indiana Pacers, the New Jersey Nets, the Denver Nuggets and the San Antonio Spurs all joined in 1976.
- On January 22, 2006, Los Angeles Lakers guard Kobe Bryant scored 81 points in a game against the Toronto Raptors. This was the second-highest single game scoring total in league history, second only to Wilt Chamberlain's 100-point game in 1962.
- Scottie Pippen (Bulls), Karl Malone (Jazz), and Reggie Miller (Pacers) had their numbers retired by their respective franchises.
- The NBA held the Hardwood Classics program for the fifth straight season. The Bulls, Rockets, Clippers, Grizzlies, Heat, Nets, Knicks, Magic, Suns, Sonics, and Wizards all took part by wearing throwback jerseys for select games.
- On the last day of the regular season, Ray Allen broke the single season record for most three-pointers, at 269.
- The NBA Finals was jokingly referred to as the "American Airlines" series since both competing teams played in an arena sponsored by the same airline. The Miami Heat play their games at American Airlines Arena (now as Kaseya Center), while the Dallas Mavericks reside in the American Airlines Center.
- All five teams in the Central Division made the playoffs, marking the first time all teams in a division made the playoffs since the entire Midwest Division made it 20 years before.
- The Los Angeles Clippers made it back to the playoffs for the first time since 1997 and won their first playoff series since 1976 when they were still known as the Buffalo Braves.
- The Los Angeles Lakers and Minnesota Timberwolves sport a patch in their warmups in memory of Hall of Fame player George Mikan, who died June 1, 2005, at the age of 80.
- On June 20, 2006, the Miami Heat clinched the NBA Finals, with Wade being the Finals MVP, averaging the third highest points per game in finals history, at 34.7, the highest points per a four-game stretch in finals history, at 39.3, and the highest PER in finals history, at 33.8.
- This marks the last season that Reebok as the official outfitter for the league until they merged with Adidas the following the season and would continue for the next ten years before Nike became the official outfitter in 2017.
- This also marks the last season for longtime Boston Celtics legend Red Auerbach's official involvement as their longtime executive before he died in October 2006.
2005–06 NBA changes
- Boston Celtics – added new green and black road alternate uniforms with black side panels to their jerseys and shorts, and they also added another new green and gold road alternate uniforms with gold side panels to their jerseys and shorts for Saint Patrick's day games only.
- Charlotte Bobcats – moved into their new arena the Charlotte Bobcats Arena, (now as Spectrum Center).
- Cleveland Cavaliers – added new dark blue road alternate uniforms added side panels to their jerseys and shorts.
- Denver Nuggets – added new dark blue road alternate uniforms with light blue side panels to their jerseys and shorts.
- Detroit Pistons – added new logo and new uniforms, added new red road alternate uniforms with blue side panels to their jerseys and shorts.
- Indiana Pacers – added new logo and new uniforms, remained with dark navy blue and gold to their color scheme and pinstripes was used during the preseason games was eventually removed to their jerseys and shorts at the start of the season.
- New Orleans/Oklahoma City Hornets – relocation from New Orleans, Louisiana to Oklahoma City, Oklahoma due to temporary move to Oklahoma City in the aftermath of the destruction of Hurricane Katrina added new logo and uniforms and split home games in New Orleans and Oklahoma City during the season.
- Sacramento Kings – added new gold road alternate uniforms with purple, grey and silver side panels to their jerseys and shorts.
- z – Clinched home court advantage for the entire playoffs
- c – Clinched home court advantage for the conference playoffs
- x – Clinched playoff spot
- y – Clinched division title
Teams in bold advanced to the next round. The numbers to the left of each team indicate the team's seeding in its conference, and the numbers to the right indicate the number of games the team won in that round. The division champions are marked by an asterisk. Home court advantage does not necessarily belong to the higher-seeded team, but instead the team with the better regular season record; teams enjoying the home advantage are shown in italics.
- * Division winner
- Bold Series winner
- Italic Team with home-court advantage
Players of the month
The following players were named the Eastern and Western Conference Players of the Month.
Rookies of the month
The following players were named the Eastern and Western Conference Rookies of the Month.