Mark Ryan Thiessen

Mark Ryan Thiessen serves as Chairman/CEO of the Thiessen Law Firm in Houston, Texas. As a criminal trial lawyer, he is Board Certified in Criminal Law by the Texas Board of Legal Specialization and in DUI Law by the DUI Defense Lawyers Association. Mark has attained the prestigious Forensic Lawyer-Scientist designation from the American Chemical Society-Chemistry and the Law (ACS-CHAL), marking the highest scientific recognition available for attorneys.

Mark frequently lectures at legal seminars, contributes to published legal articles, and teaches as a faculty member for multiple organizations. He co-chairs the DWI Committee and serves on the Board of Directors for the Texas Criminal Defense Lawyers Association (TCDLA) and the Harris County Criminal Lawyers Association (HCCLA). Additionally, he is a Charter Member and Director for the DUI Defense Lawyers Association (DUIDLA).

With six appearances as a Texas Super Lawyer and inclusion in the Top 100 Super Lawyers in Houston for 2017 and 2018, Mark was uniquely honored in 2019 as the only criminal lawyer named among the Top 100 Super Lawyers in all of Texas. His legal prowess is demonstrated by victories in DWI cases ranging from total refusals to complex quadruple intoxication manslaughter cases.

Beyond the courtroom, Mark is an accomplished Brown Belt in Brazilian jiu-jitsu, practices Muay Thai, and competes in events like the Warrior Dash and Tough Mudder. He is also passionate about snow skiing, wakeboarding, and playing tennis.