Monica C. Yun is a Partner at Keystone Law Group, P.C., practicing primarily in trust and estate litigation matters. She has successfully represented trustees, personal representatives, beneficiaries, heirs, creditors, and conservators in connection with probate litigation and administrative matters. Monica has litigated matters concerning, without limitation, trust contests, will contests, creditor’s claims, inheritance rights, fiduciary appointments and removals, financial elder abuse claims, heirship claims, 850 petitions, and contested conservatorship issues. Monica has appeared before courts in Los Angeles County, Orange County, Riverside County, San Bernardino County, and Kern County.

Monica was selected by Super Lawyers Magazine as a Rising Star in 2018-2020; 2022-2023. She was also included in “Top Women Attorneys of Southern California,” a special section in the September 2018 issue of Los Angeles magazine. In 2024, Monica was named to The Best Lawyers in America by Best Lawyers®: Ones to Watch list in the categories of Litigation – Trust and Estates; Trusts and Estates

Monica joined Keystone in March 2015 and immediately began to impress her colleagues and clients. Monica has demonstrated an innate ability to quickly master complex legal issues, and her colleagues have utilized her skills and abilities to contribute to many of the firm’s most challenging probate litigation matters over the past few years. As Monica’s skill set has developed, she is serving as the primary handling attorney for many of the firm’s cases. We are excited to continue to have Monica as an integral part of the team. 

Publications / Speaking Engagements

  • Fiduciary Misconduct Involving Trusts, CEB, Practitioner, December 7, 2023.
  • Strategic Considerations in Requesting Beneficiary Approval of Trustee's Proposed Action (original publication date: August 16, 2021; updated: June 10, 2022), CEB, Practitioner.
  • Attorney Fee Agreement for a Probate Administration (original publication date: July 19, 2021; updated: June 26, 2022), CEB, Practitioner.
  • Attorney-Client Fee Agreement, Representing the Trustee (original publication date: July 19, 2021; updated: June 26, 2022), CEB, Practitioner.
  • How to Identify and Classify the Heirs and Beneficiaries (original publication date: October 8, 2021; updated: June 21, 2022), CEB, Practitioner.
  • Estate Planning and Administration, National Business Institute (NBI), Topic: “Probate Process Overview” September 15, 2017.
Monica C. Yun

Monica received her undergraduate degree from the University of California Los Angeles, graduating magna cum laude, and her law degree from the University of California, Hastings College of the Law. 


  • California Lawyers Association, Trusts & Estates and Litigation Sections
  • Los Angeles County Bar Association, Trusts & Estates and Litigation Sections
Representative Matters
  • Advised trustees and personal representatives in trust and estate administration matters valued from several hundred thousand dollars to millions of dollars.
  • Successfully settled numerous probate litigation matters, to achieve favorable results for trustees, executors, heirs and beneficiaries.
  • Successfully litigated from inception to settlement, myriad trust and estate matters surrounding the validity of a decedent’s estate planning documents.
  • Successfully represented heirs and beneficiaries in cases involving claims of financial and physical elder abuse, undue influence, and lack of testamentary capacity.
  • Successfully represented trustees and beneficiaries in trust accounting disputes, including requests to compel trustees to provide a trust accounting, make distributions, and sell trust real property.
  • Successfully represented family members and loved ones in initiating conservatorship proceedings in order to allow the conservator to make important legal, medical, and financial decisions for the incapacitated individual.


Outside of the office, Monica is a cinephile and enjoys spending time with her husband, daughters, and dog.