2018–19 Dallas Mavericks season

The 2018–19 Dallas Mavericks season was the 39th season of the franchise in the National Basketball Association (NBA). With an overtime loss to the New Orleans Pelicans on March 18, the Mavericks would once again have a losing season and not make the playoffs for the third consecutive year.

It was Dirk Nowitzki's 21st and final season with the Mavericks, making his season debut on December 13, 2018 against the Phoenix Suns. Not only would he break a record previously set by Kobe Bryant for the most seasons spent playing for a single NBA team, but he also became the fifth player in the NBA history to play in the league for 21 seasons. Believed by many as the greatest Maverick of all time, Nowitzki led the Mavs to 15 playoff appearances (2001-2012; 2014-2016), to a Finals appearance in 2006, and to their first championship title in 2011, defeating the Big 3-led Miami Heat. A 14-time NBA All-Star, Nowitzki is the first European player to start in an All-Star Game, and the first to win the MVP Award. He is also the highest scoring foreign-born player in NBA history and on March 18, 2019, became the 6th highest scoring player of all time, surpassing Wilt Chamberlain's 31,419 points. Nowitzki's retirement leaves former Maverick and fellow 1998 draftee Vince Carter (who played for the Atlanta Hawks) as the last remaining active player to have played in the 1990s. Additionally, Carter became the first player to play in 4 different decades after retiring the following season, a record that Nowitzki could have possibly achieved prior to announcing his retirement on April 9, 2019.

On January 31, 2019, the Mavericks acquired NBA All-Star Kristaps Porziņģis in exchange for Wesley Matthews and former no. 9 overall pick Dennis Smith Jr.

This was the last time that the Mavericks missed the playoffs until 2023.