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 Massachusetts, when child custody, visitation, or support is contested, the courts have the authority to appoint a guardian ad litem (GAL) to investigate and make recommendations regarding the best interests of the child. The GAL, who is often an attorney with expertise in family law, is tasked with conducting a thorough investigation which includes interviewing the child, parents, and others in the child's life. The GAL has the power to subpoena witnesses and to examine and cross-examine them during court hearings. After completing the investigation, the GAL will report their findings and provide recommendations to the court. The GAL's testimony can be influential in the court's decisions regarding custody, visitation, and support. The appointment and role of the GAL are governed by Massachusetts state statutes and family court procedures, ensuring that the child's welfare is the paramount concern in contested family law matters.