The 2011–12 Dallas Mavericks season was the 32nd season of the franchise in the National Basketball Association (NBA). They were attempting to win back-to-back NBA Finals but were eliminated in the first round by a sweep against the Oklahoma City Thunder.

The season officially began once NBA players and owners signed a new collective bargaining agreement to end the 2011 NBA lockout.

At the Draft night the Mavs acquired Rudy Fernández for their 26th pick, Jordan Hamilton who was sent to Denver.

The Mavericks went into the offseason with six free agents. Tyson Chandler verbally committed to a deal with New York, while Caron Butler signed a three-year deal worth $24 Million with the Los Angeles Clippers. They signed Forward Brandan Wright on December 9. The Mavericks got Andy Rautins from the Knicks in a three-team trade. He was waived just shortly after. On December 10, Brian Cardinal announced on his Twitter account that he has re-signed with the Mavs and was made official on December 12.Vince Carter signed a contract on December 11, while Lamar Odom came to the Mavs through a trade with the Los Angeles Lakers.Drew Neitzel and Jerome Randle were signed on December 11. The Mavs signed Delonte West on December 12 to a one-year deal. The Mavericks traded Rudy Fernández and Corey Brewer to the Denver Nuggets for a future second-round pick. On December 14, José Juan Barea announced that he would join the Minnesota Timberwolves.Peja Stojaković announced on December 19, his retirement. The Mavericks signed Sean Williams on December 21 to a two-year deal. Neitzel and Randle were both waived on December 21 after playing with Williams in the D-League for the Texas Legends.DeShawn Stevenson signed a one-year deal with New Jersey.Free agent Yi Jianlian was signed on January 6, to a 1-year deal.