A court-appointed representative, often an attorney, who advocates for a child's best interests in custody proceedings.
Example
The guardian ad litem interviewed the children and recommended shared custody.
Canadian Equivalent
In Canada, this is referred to as Office of the Children's Lawyer (ON) / Child's Legal Representative / Children's Advocate.
Jurisdiction Variations
Minor's Counsel
California appoints 'minor's counsel' (Family Code §3150) rather than a GAL
Amicus Attorney / Attorney ad Litem
Texas distinguishes: 'amicus attorney' advises court; 'attorney ad litem' represents child
Child and Family Investigator (CFI) / Parental Responsibilities Evaluator (PRE)
Colorado uses CFI for investigation and PRE for comprehensive evaluation
Friend of the Court
Michigan has a unique 'Friend of the Court' office that investigates and makes custody recommendations