When child custody, visitation, or support is contested in a divorce or other legal proceeding, courts may appoint a guardian ad litem (often an attorney with experience in family law matters) to investigate and make independent, objective recommendations to the court of what is in the best interest of the child. The guardian ad litem will typically interview the child, the parents, and other people who have contact with the child, and may subpoena witnesses to testify at court hearings, examine and cross-examine witnesses at hearings. The guardian ad litem may also testify regarding her investigation of the circumstances, conclusions, and recommendations to the court.

In New Hampshire, when child custody, visitation, or support is contested, the court may appoint a guardian ad litem (GAL), who is often an attorney with experience in family law, to represent the best interests of the child. The role of the GAL is to conduct an independent investigation, which includes interviewing the child, parents, and others in contact with the child. The GAL has the authority to subpoena witnesses and to examine and cross-examine them during court hearings. After completing the investigation, the GAL will report their findings, conclusions, and recommendations to the court. The court then considers the GAL's recommendations when making decisions regarding custody, visitation, or support. The appointment and responsibilities of a GAL in New Hampshire are governed by state statutes, including RSA 461-A:16, which outlines the qualifications, duties, and the scope of the authority of a GAL in family law matters.