1999–2000 Dallas Mavericks season

The 1999–2000 NBA season was the Mavericks' 20th season in the National Basketball Association. This season is especially notable as Mark Cuban purchased the team from Ross Perot Jr. in January 2000. Under Cuban's leadership, the Mavs built a foundation for continued NBA success that eventually led to two Finals appearances (and one championship) in the next decade. During the off-season, the Mavericks re-acquired former center Sean Rooks from the Los Angeles Lakers.

The Mavericks continued to struggle with a 9–23 start, as Gary Trent only played just eleven games due to hamstring and groin injuries, and Hot Rod Williams was out for the entire season with a back injury. However, after the slow start, the team then won 11 of their next 15 games. At midseason, the Mavs signed flamboyant power forward Dennis Rodman on February 3, a month after Cuban bought the team. However, Rodman's behavior issues led to a very short (12 game) tenure in Dallas before he was released to free agency in early March. The Mavericks held a 20–28 record at the All-Star break, then later on won nine of their final ten games in April, and finished fourth in the Midwest Division with a 40–42 record. However, they missed the playoffs for the tenth straight season.

Michael Finley averaged 22.6 points, 6.3 rebounds, 5.3 assists and 1.3 steals per game, and was selected to play in the 2000 NBA All-Star Game in Oakland, California, while second-year star Dirk Nowitzki showed improvement, averaging 17.5 points and 6.5 rebounds per game, and Cedric Ceballos provided the team with 16.6 points and 6.7 rebounds per game. In addition, Erick Strickland contributed 12.8 points and 1.5 steals per game, while Robert Pack provided with 8.9 points and 5.8 assists per game, but only played just 29 games due to a sprained ankle, Steve Nash contributed 8.6 points and 4.9 assists per game, but only played 56 games due to an ankle injury, Shawn Bradley averaged 8.4 points, 6.5 rebounds and 2.5 blocks per game, and Hubert Davis contributed 7.4 points per game off the bench, while shooting .491 in three-point field goal percentage. Nowitzki also finished in second place in Most Improved Player voting, while Ceballos finished tied in third place in Sixth Man of the Year voting.

Following the season, Ceballos was traded to the Detroit Pistons, while Strickland was traded to the New York Knicks, Rooks was dealt to the Los Angeles Clippers, Pack and Williams were both dealt to the Boston Celtics in a four-team trade, who then sent Pack back to his former team, the Denver Nuggets, and released Williams to free agency as he retired.