Kathleen Zellner is an American attorney who has worked extensively in wrongful conviction advocacy.

Notable clients Zellner has represented include Steven Avery (who was the subject of the 2015 and 2018 Netflix series Making a Murderer), Kevin Fox (who was falsely accused of murdering his daughter), Ryan W. Ferguson, Larry Eyler, and 19 exonerees who are listed in the National Registry of Exonerations.

[11][8] She opened her firm, Kathleen T. Zellner & Associates in Downers Grove, Illinois, in 1991.

[10][12][13] Notable clients Zellner has represented include Steven Avery (who was the subject of the 2015 and 2018 Netflix series Making a Murderer), Kevin Fox (who was falsely accused of murdering his three-year-old daughter), and 19 exonerees who are listed in the National Registry of Exonerations.

[12] In 2000, The National Law Journal named Zellner a top ten trial lawyer in the United States for a suicide malpractice verdict of $13 million.