Debrán O’Neil
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Debrán O’Neil

I understand clients need more from a litigator than effective advocacy skills; they need an advisor who they can trust to guide them through stressful times. I enjoy using my extensive experience and ability to relate to others to make clients feel comfortable and confident throughout the dispute process. I walk them through step by step, explain key issues in layman’s terms, and lay out their options and the pros and cons of each potential path.

Debrán O’Neil is a well-rounded trial lawyer who practices commercial litigation and health law. Her experience handling commercial cases across a wide variety of industries gives her the adaptability necessary to quickly learn the case and drill down on the key issues. Debrán draws on her experience handling business disputes, breach of contract actions, fraud and fiduciary duty litigation, products liability, personal injury defense, construction litigation, and real estate disputes to guide her clients through litigation strategies.

As part of her healthcare practice, Debrán represents hospital facilities, physicians, and other healthcare-adjacent organizations in business disputes and medical negligence cases. She advises on matters related to peer review, physician credentialing, Stark, Anti-kickback, False Claims Act, HIPAA, and the HITECH Act. Debrán has a deep respect for the service healthcare professionals provide and appreciates the opportunity to serve them with her own hard work.

When litigation proves to be the best course of action, Debrán adeptly handles all aspects of trial—from formulating an overall strategy, taking depositions of fact and expert witnesses, drafting and arguing motions, managing discovery, and coordinating with various local and national parties, to preparing for and taking cases through trial or arbitration. She brings excellent advocacy skills to the courtroom and relishes the chance to promote her clients’ interests to a judge or jury.

Debrán advocates vigorously for her clients with poise and professionalism. She finds that building respect with all parties is the most effective way to accomplish her clients’ goals. Debrán knows how to calibrate her communication style to her audience and scales her litigation skills to fit the size and scope of each matter. She always looks for ways to resolve cases with the smallest investment of her client’s time and money.

I enjoy using my extensive experience and ability to relate to others to make clients feel comfortable and confident throughout the dispute process.

Debrán L. O’Neil

Significant Matters

Representative Healthcare Matters

  • Obtained summary judgment for a hospital in a medical malpractice case by striking the plaintiff’s expert on causation. The case was affirmed on appeal, and the Texas Supreme Court denied the petition for review.
  • Successfully defended hospitals and physicians in medical malpractice cases involving catastrophic injuries, including birth and traumatic brain injuries.
  • Represented and advised hospitals in credentialing and peer review matters.
  • Represented a physician in litigation against her former practice group over the value of her equity in the company.
  • Represented owner of an integrated chiropractic clinic in a partnership dispute with other owners.

Representative Personal Injury and Products Liability Matters

  • Represented commercial landowner in personal injury claim resulting from the fall of a subcontractor’s employee.
  • Successfully defended valve and electrical manufacturers in products liability cases, including toxic tort.
  • Represented national restaurant chains in the defense of personal injury claims alleging food contamination and food-borne illnesses.
  • Represented national supplier of construction materials in personal injury claim, including defending claims from other defendants for contractual indemnity.

Representative Commercial Litigation Matters

  • Represented national bank in obtaining multi-million-dollar judgments against guarantors on commercial loans, including defending claims for fraudulent inducement and defeating other defenses.
  • Represented a large regional firm against claims brought by the bankruptcy trustee of a former client alleging the firm aided and abetted the client’s allegedly fraudulent business practices. The plaintiff sought over $129 million in damages.

Areas of Focus



  • Baylor Law School (J.D., summa cum laude, 2012)
    • Baylor Law Review, 2010-12: Managing Senior Executive Editor
    • Order of Barristers
  • Southwestern University (B.A., magna cum laude, 2009)
    • Hatton Sumners Fellow


Bar Admissions
  • Texas, 2012
Court Admissions
  • U.S. District Court, Northern District, Texas
  • U.S. District Court, Southern District, Texas
  • U.S. District Court, Eastern District, Texas
  • U.S. District Court, Western District, Texas


  • Texas Health Lawyers Association
  • Patrick E. Higginbotham American Inn of Court, Associate, 2015-2016
  • Dallas Association of Young Lawyers, 2014 Leadership Class
  • Dallas Association of Young Lawyers, Trial Skills Boot Camp, Co-Chair
  • Dallas Association of Young Lawyers, Judiciary Committee
  • Dallas Bar Association, Transition to Law Program Advisor
  • Texas Bar Association
  • Attorneys Serving the Community, Heart & Sole 5k Committee


  • Named to D Magazine's "Best Lawyers Under 40 in Dallas" List, 2020, 2023, 2024
  • Lawdragon 500, Leading Litigators in America, Accounting & Other Professional Liability, Product Liability, 2023-2024
  • Named to the Texas Super Lawyers list, as published in Texas Monthly magazine, 2023
  • Best Lawyers in America: Ones to Watch, 2022-2024, Commercial Litigation; Health Care Law; Medical Malpractice Law - Defendants, Professional Malpractice Law
  • Honored as Top 100 Texas Up & Coming lawyer as published in Texas Monthly magazine, 2021
  • Honored as Top 50 Women Texas Up & Coming lawyer as published in Texas Monthly magazine, 2021
  • Honored as a Rising Star in Business Litigation as published in Texas Monthly magazine, 2016-2022

Best-Lawyers-Logo (1)DO-RS21 DO-RS21-50 DO-RS21-100


  • Speaker and Author: Trust and Confidence: Pursuing and Defending the Informal Fiduciary, State Bar of Texas 18th Annual Fiduciary Litigation CLE, December 2023
  • Speaker: The Ethics of Working with Witnesses and Experts, presented with trial consultant Jeff Dougherty (2020).
  • Moderator, DAYL Skills Boot Camp Series, Direct Examination, Dallas (2019).
  • Co-Author, SMU Annual Texas Survey: Professional Liability, 2 SMU Ann. Tex. Surv. 363 (2016).
  • Co-Author, Professional Liability, SMU L. Rev. (2015).
  • Co-Author, Doing Business With Health Care Providers, Carrington Coleman Capital Newsletter (Spring 2013).
  • Co-Author, Six Things Every Lawyer Should Know About Health Law, DBA Headnotes (March 2013).
  • Co-Author, Professional Liability, 66 SMU L. Rev. 1055 (2013).

Outside of Work

Debrán and her husband have two little girls and enjoy spending family time together, especially outside and near water. She likes traveling, cooking, and reading books on the front porch.