Thiessen Law Firm

Thiessen Law Firm is a Houston DWI defense firm led by Mark Thiessen, America's only triple board-certified DWI attorney. The firm has won over 100 not guilty verdicts and dismissed 1,000+ cases. Mark defeated a quadruple intoxication manslaughter charge. He's the only DWI lawyer in the Top 100 Texas Super Lawyers (2019-2023). Clients get 24/7 direct access to their legal team. The firm handles complex DWI cases throughout Texas.

Last Updated: October 06, 2026