Guardian ad Litem: Definition and How It Works in California

By Eric Ridley, attorney, Ridley Law. Updated September 2026.

A guardian ad litem is a person the court appoints to represent the interests of a minor or an incapacitated person in a probate or trust proceeding when that person can’t represent themselves.

How it works in California

Prob. Code, § 1003 lets the probate court appoint a guardian ad litem on its own motion or on the request of a personal representative, guardian, conservator, trustee, or other interested person. The appointment is limited to that one proceeding; it doesn’t give the guardian ad litem any authority over the minor or incapacitated person outside the courtroom.

The role shows up most often when a minor child stands to inherit directly, when a beneficiary is missing or unknown, or when someone with an interest in the outcome can’t meaningfully participate because of age or incapacity. The guardian ad litem investigates the situation and reports to the court on what outcome serves that person’s interest.

A guardian ad litem isn’t the same as a guardian appointed to raise a child or manage their property long-term, and it isn’t a conservator. The role ends when the specific proceeding does.

Why it matters

For example, a trust settlement involves a 9-year-old beneficiary whose parents also stand to benefit from the same settlement. The court appoints a guardian ad litem so someone without that conflict is looking out for the child’s share before the judge approves the deal.

Common mistakes

Assuming a parent can automatically speak for a minor beneficiary in a probate or trust proceeding, even when the parent has a competing interest in the outcome. Confusing a guardian ad litem with a guardianship of the person or estate, which is a separate, ongoing role. Waiting until a hearing is already underway to raise the need for one.

Related terms

• Conservatorship: a longer-term court appointment for an adult, compared to this proceeding-specific role.
• Guardianship: the ongoing appointment to raise a child or manage their property, distinct from representing that child in one case.
• Testamentary capacity: an issue that can trigger the need for a guardian ad litem when a party’s capacity is itself in question.

Part of the California estate planning glossary.