Parenting plans—also known as custody agreements or custody and visitation agreements—are proposals submitted by parents for how issues involving children should be handled following a divorce or other proceeding in family court. The court will usually request the parents submit such a document proposing how conservatorship (decision-making), custody or possession, support, and other issues will be handled. The court may adopt some or all of these proposals and include them in the court’s order (divorce decree, child support and custody order), at which point the become legally enforceable.

In many states there is a standard possession order (SPO) that serves as the default terms for such matters, and as a useful starting point for parents who wish to modify it by agreement.

In Illinois, parenting plans are required in cases involving child custody, which is referred to as the allocation of parental responsibilities. These plans must outline how both parenting time (formerly known as visitation) and significant decision-making responsibilities will be divided between the parents. Illinois law encourages parents to work together to create a parenting plan that serves the best interests of the child. If the parents cannot agree on a plan, each parent may submit their own proposal, and the court will make a determination. The parenting plan must be submitted within 120 days of filing for custody or divorce. Illinois does not use the term 'standard possession order' as some other states do, but the state does provide guidelines to help parents create a plan that will be in the best interest of the child. Once the court approves a parenting plan, it becomes legally binding and enforceable. Modifications to the plan can be made if there is a significant change in circumstances, but they must also be approved by the court.