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like No Other for Your Case Free Consultation
  • "The BEST attorney in Harris County and probably one of the best in the nation."
  • "The Best Law Firm in the Industry"
  • "If you want a GREAT lawyer, Mark Thiessen is your man."
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Not Guilty Verdicts
  • .171 Breath Test - Not Guilty
  • 0.119 Blood Test - Not Guilty
  • 0.158 Blood Test - Not Guilty
See Our Results

Let Us Fight For You

Aggressive Trial Lawyers Serving Houston

A DWI arrest, drug charge, custody battle, or serious accident can impact your life in so many ways. You need a true fighter on your side to set your life back on track. At Thiessen Law Firm, our Houston trial lawyers always fight our hardest. We tell the truth about our clients’ cases because facts take precedence over promises. Honesty and integrity provide the foundation of our practice and help ensure each case ends with a positive result.

When it comes to your future, do not settle for subpar legal counsel. Choose a top-notch firm with a reputation for real results. We have secured over 100 Not Guilty verdicts in a variety of complex cases – proof of our skill and our commitment to our clients. We also have the training and experience needed to protect your rights effectively. Mark Thiessen is recognized as an ACS CHAL Lawyer-Scientist for his understanding of the science and technology behind DWI testing. He is also Board Certified in DUI Law by the DUI Defense Lawyers Association.

From complex DWI charges and painful personal injury claims to emotionally-charged family law matters, you can count on our team to treat you like family, putting our heart and soul into the battle for your future.

Call (713) 864-9000 today or contact us online for a free, confidential case evaluation.

Meet Our Legal Team

As one of Houston’s most distinguished criminal defense firms, Thiessen Law Firm emphasizes quality over quantity. We will get to know your case better than anyone and will utilize every tool at our disposal to secure the results you need. We are dedicated to your needs – 24 hours a day, 7 days a week. As soon as you hire us, you will receive the direct contact information on everyone on your case.

Meet Our Team
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  • ACS/CHAL Lawyer Scientist
  • Top 100 Super Lawyers in Houston - 2017-2018
  • Super Lawyers
  • DUIDLA - Board Certified
  • Texas Criminal Defense Lawyers Association (TCDLA)
  • National College for DUI Defense
  • The National Trial Lawyers Top 100
  • Avvo 10.0
  • AV Preeminent Rated by Martindale-Hubbell

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Why Choose
Thiessen Law Firm?

  • Aggressive Trial Attorneys
  • Dedicated Team to Fight for You
  • 100% Client Satisfaction
  • Free Case Evaluation
  • 24/7 Accessibility
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In the Community

Over the past years, Thiessen Law Firm has taken pride in giving back to the community and has donated to a number of non-profits and events, such as those featured below. If your non-profit or charity is interested in sponsorship from Thiessen Law Firm, contact us today!

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A Texas DWI Can Cost You $15,000

Get the DWI facts no Texan should drive without, including:
  • 3 rights you can exercise when you get pulled over
  • How to save your license from suspension
  • Why you should refuse any roadside tests
  • What to say during your booking
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