On July 9, 2015, Pachulia was traded to the Dallas Mavericks in exchange for a future second-round pick. He made his debut for the Mavericks in the team's season opener against the Phoenix Suns on October 28, recording a double-double with 10 points and 10 rebounds in a 111–95 win. On December 26, he recorded his 16th double-double of the season with 17 points and 12 rebounds against the Chicago Bulls, surpassing his 2014–15 season total. On January 12, 2016, he recorded his 20th double-double of the season, and the 100th in his career, with 14 points and 12 rebounds in a 110–107 overtime loss to the Cleveland Cavaliers. Later that month, he came within 14,227 votes of knocking out San Antonio Spurs small forward Kawhi Leonard for a starting spot on the West All-Star team for the 2016 NBA All-Star Game. On February 3, 2016, he recorded 10 points and 15 rebounds against the Miami Heat for his career-best 22nd double-double of the season. His previous best was 21 double-doubles, set with Atlanta in 2005–06.