O’Melveny Worldwide

Rex VanMiddlesworth focuses his practice on commercial litigation, administrative law, energy, and alternative dispute resolution. He has tried cases in state court, federal court, before arbitration panels, and before state and federal agencies. Rex has also handled appeals in the Fifth Circuit, the Texas Supreme Court, and various Texas Courts of Appeals. He has extensive experience representing public and private entities in breach of contract disputes, tortious interference cases, and other forms of commercial litigation and arbitration. Rex handles all types of contested proceedings before state agencies and the State Office of Administrative Hearings, including licensing and rate-setting disputes. He also has represented a number of clients in constitutional and voting rights litigation.

Rex has been recognized by numerous publications for his outstanding legal career, including The Best Lawyers in America®, Chambers USA, and Texas Super Lawyers. He was named the 2016 Austin Energy Regulatory “Lawyer of the Year” by The Best Lawyers in America and in 2005, the Austin Business Journal recognized Rex as the best public law and administrative litigator in Austin in its inaugural “Best of the Bar” Awards. He is a frequent author and lecturer at conferences and seminars on issues, including topics of evidence, ethics, constitutional litigation, and administrative litigation. Before beginning his law practice, Rex was awarded a Teaching Fellowship in Constitutional Law at Harvard University under Professor Archibald Cox.

“Rex VanMiddlesworth is recognized for his skillful representation of energy clients in administrative proceedings and civil litigation. Sources say ‘he has decades of experience representing industrial customers, does well for his clients and is very successful in rate cases and other proceedings.’” –Chambers USA 2020


Bar Admissions

  • Texas

Court Admissions

  • US Supreme Court
  • US Court of Appeals, Fifth Circuit
  • US District Court, Southern District of Texas
  • US District Court, Western District of Texas


  • Harvard Law School, J.D., 1980: cum laude
  • Indiana University, B.S., 1977: summa cum laude

Honors & Awards

  • Recognized by Chambers USA in Energy: State Regulatory & Litigation (Electricity) (2011-2020, 2022-2024)
  • Recognized by Best Lawyers® for Administrative / Regulatory, Energy Law, Energy Regulatory Law, and Utilities Law in Austin, TX (1995-2024); Rex has been listed in Best Lawyers® since 1995
  • Recommended by The Legal 500 US for Energy Regulation: Electric Power (2015-2020, 2023-2024); Energy: Litigation (2015-2020, 2023); Energy Regulation: Conventional Power) (2015-2020, 2023)
  • Top Rated Litigators, The American Lawyer, 2021
  • Austin (Energy Regulatory Law) Lawyer of the Year, The Best Lawyers in America, 2012, 2016
  • Texas Super Lawyers by Thomson Reuters (Business Litigation), 2003-2020
  • Most Outstanding Public Law and Administrative Litigator, Austin Business Journal, Inaugural Best of the Bar Awards, 2005
  • Life Fellow, American Bar Foundation
  • Life Fellow, Texas Bar Foundation

Professional Activities


  • Travis County Bar Association
  • American Bar Association
  • The University of Texas McDonald Observatory; Board of Visitors
  • First Amendment Museum; Board of Directors