Child custody (also known as legal custody, conservatorship, or allocation of parenting time and responsibilities) refers to the legal possession, rights, and responsibilities for a minor child by the child’s birth or adoptive parents—including the right to make health care, religious, cultural, and education decisions about the child's upbringing.

During separation, and following divorce, a child’s natural parents often share custody of the child (shared custody or joint custody)—unless one or both of the child’s natural or adoptive parents are deemed to be unfit or pose a risk to the health, safety, and well-being of the child (the child’s best interests). If one of the parents is deemed unfit, the other parent may be awarded sole custody of the child. In some cases a parent who is not allowed to have custody of a child may be given visitation rights—sometimes under the supervision of another adult (supervised visitation). Child custody laws are usually located in your state’s statutes governing family and domestic matters, and may be referred to as the Family Code.

Child custody is distinct from guardianship of a child, which usually involves a relative or an unrelated person temporarily agreeing to take responsibility for a child following the death of the child’s birth or adoptive parents, or their abandonment. And adoption is taking full and permanent responsibility for a child by someone other than the child’s birth parents.

In Massachusetts, child custody laws are designed to ensure the best interests of the child are the primary consideration in custody and visitation matters. The state recognizes several types of custody arrangements, including sole custody, where one parent has primary responsibility for the child, and shared or joint custody, where both parents share responsibilities. Massachusetts courts consider various factors when determining custody, such as the child's relationship with each parent, the parents' ability to provide for the child's needs, and the child's adjustment to home, school, and community. If a parent is deemed unfit due to reasons such as abuse, neglect, or substance abuse, they may lose custody rights. However, they may be granted visitation rights, which can be supervised if necessary to protect the child's well-being. The relevant statutes are found in the Massachusetts General Laws under the sections pertaining to domestic relations and family law. It's important to note that child custody is distinct from guardianship, which may be established when a child's parents are deceased or unable to care for them, and from adoption, which is the permanent legal assumption of parental responsibility by an individual other than the child's birth parents.