Brett Allen Chapman

Brett Chapman is a highly experienced Oklahoma attorney who combines his comprehensive knowledge of Oklahoma law with a passion for justice that finds its roots in his unique family history.

Brett’s maternal great great great grandfather Chief White Eagle was the hereditary chief of the Ponca during the illegal Ponca Trail of Tears in 1877. His ancestor's against-all-odds fight for justice inspired him to become an attorney and seek justice for others.

Brett started his legal career by serving seven years in the District Attorney's Office, where he handled every kind of case possible, from misdemeanors to homicides. He also successfully changed Oklahoma's DUI case law as a prosecutor in 2015 by advocating for the change in a comprehensive legal briefing which persuaded Oklahoma's highest appellate court to change the law, State v. Alba, 2015 OK CR 2, 341 P.3d 91, and litigated a case which resulted in strengthening laws regarding sex offenders. See Weeks v. State, 2015 OK CR 16, 362 P.3d 650.

He has also defended many high profile complex litigations, including two recent appellate cases involving a novel legal issue on the cutting edge of the landmark 2020 SCOTUS ruling in McGirt v. Oklahoma involving state criminal jurisdiction over American Indians in Eastern Oklahoma. See City of Tulsa v. O'Brien, 2024 OK CR 31, __ P.3d __ and Stitt v. City of Tulsa, 2025 OK CR 5, __ P.3d __. In the Stitt case, the United States government filed an extremely rare amicus brief supporting his claim and the Biden administration cited this in the 2024 White House Tribal Nations Summit Report. The case has a chance to be taken up by SCOTUS in 2026.

Upon leaving the District Attorney's Office, he became a defense attorney for the Union Pacific Railroad Company and the BNSF Railway Company and defended both companies in complex wrongful death cases. His practice is now focused on criminal defense and advocating for Native American rights and tribal sovereignty in the spirit of his ancestors.

Brett is licensed to practice law in the following jurisdictions:

- Oklahoma Bar Association (No. 30334)
- Supreme Court of the United States (No. 322005)
- United States Court of Appeals for the Tenth Circuit
- United States District Court for the Northern District of Oklahoma
- United States District Court for the Eastern District of Oklahoma
- Muscogee (Creek) Nation (No. 1107)
- Cherokee Nation (No. 850)
- Choctaw Nation (No. 424)
- Osage Nation