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 Washington State, child custody laws are designed to ensure the best interests of the child are prioritized during and after the parents' separation or divorce. Child custody, which includes both physical and legal custody, can be awarded as either joint custody, where both parents share responsibilities and time with the child, or sole custody, where one parent has the majority of responsibilities and time with the child. Washington courts consider various factors to determine custody arrangements, such as the child's relationship with each parent, the parents' health and lifestyle, and the child's adjustment to home, school, and community. If a parent is deemed unfit, the other parent may be granted sole custody. Unfit parents may receive supervised visitation to ensure the child's safety. The state's child custody laws are found within the Revised Code of Washington (RCW), particularly in Title 26, which pertains to domestic relations. These laws outline the procedures and considerations for determining custody and visitation arrangements. It's important to note that child custody is different from guardianship, which is a temporary arrangement typically made when the child's parents are deceased or have abandoned the child, and from adoption, which is a permanent legal transfer of all parental rights from the child's birth parents to the adoptive parents.