Maggie Diefenbach, Partner, Board of Directors
  • Maggie began her legal career as litigation counsel for an insurance company over 18 years ago.  She has been litigating personal injury and property damage claims ever since, serving as counsel to insurance companies, individuals and businesses.  Maggie defends lawsuits involving motor vehicle accidents, premises liability, products liability, employment issues, workplace injuries, retail and hospitality, and first-party insurance disputes.

    Over the course of her career, Maggie has litigated over 1,000 cases and strives to resolve cases in a strategic and efficient manner. When settlement is not an option, Maggie fiercely advocates for her clients at trial. She has successfully tried jury cases throughout Washington State and has obtained a defense verdict or bested her client’s last pre-trial settlement offer in her last five jury trials.

  • Education

    • J.D., University of Southern California School of Law, 2000
    • B.A., Pacific Lutheran University, 1997
    • magna cum laude

    Jurisdictions Admitted to Practice

    • Washington State Bar, 2001
    • United States District Court, Western District of Washington

    Professional & Bar Association Memberships

    • Washington State Bar Association

    • King County Bar Association

    • Washington Women Lawyers

    • Defense Research Institute

    • Washington Defense Trial Lawyers

    • National Diversity Council

    Professional History

    • State Farm Mutual Automobile Insurance Company, 2001-2003
    • Cozen O'Connor, 2003-2010
    • Betts Patterson & Mines, 2010-2015
    • Gordon Thomas Honeywell LLP, 2015-present
    • Chair, GTH Defense Litigation Group
    • Member, GTH Board of Directors, 2018

    Honors & Awards

    • Recipient of the 2015 Outstanding Mentor Award by the King County Bar Association Young Lawyers Division

    Articles & Presentations

    • Defending Washington Auto Claims A-Z, Client Seminar, 2012
    • Defending Washington Insurance Claims, Client Seminar, 2014
    • Defending Washington Auto Claims, Client Seminar, 2016
    • National Diversity Council Seattle Women in Leadership Symposium, 2017
  • Recent Jury Trials

    • Maggie defended a client tavern owner from the beginning of the case through the appeal. The plaintiff became a quadriplegic due to injuries in a motor vehicle accident. The plaintiff sued the tavern and two other bars that served the driver alcohol, declaring that the driver was under the influence of alcohol at the time of service. Maggie successfully barred hearsay evidence and prevailed on summary judgment and prevailed again on appeal. Plaintiff’s petition to the Washington Supreme Court was denied. Ensley v. Mollmann, 155 Wn. App. 744 (2010)

    • In a wrongful death action arising out of a bar fight, Maggie defended the owner of a Seattle nightclub. The deceased’s estate and surviving child sued the nightclub and its security company, claiming that the security company neglected to intervene and secure a weapon in a bar brawl in which a patron died. The trial court dismissed the liability claim against the nightclub, holding that it was not vicariously liable for the security company’s acts or omissions because it was an independent contractor, not the nightclubs' agent, as argued by the plaintiffs.

  • Fireboats on the Seattle Waterfront
  • Tacoma Arches at the History Museum
  • Pioneer Square
  • Reflection pond by the Tacoma Glass Museum
  • Duwamish Waterway and brown field cleanup
Gordon Thomas Honeywell LLP


1201 Pacific Ave, #2100
Tacoma, WA 98402

Telephone: 253.620.6500
Fax: 253.620.6565


One Union Square
600 University St, #2100
Seattle, WA 98101

Telephone: 206.676.7500
Fax: 206.676.7575

Visit the Gordon Thomas Honeywell Governmental Affairs Web Site


1201 Pacific Ave, #2100, Tacoma, WA 98402
Telephone: 253.620.6500  Fax: 253.620.6565


One Union Square, 600 University St, #2100, Seattle, WA 98101
Telephone: 206.676.7500  Fax: 206.676.7575