Custody is a court-ordered arrangement providing for the care of a minor child by the parents. A third-party custodian may be appointed by the court if necessary to fulfill the obligations that would normally be handled by the parents. Custody is decided based on what is in the best interest of the child. Parents have preference over others to custody of their child. If contested, a parent must be found unfit before a third-party may be awarded custody of the child. Shared ("joint") custody is customary, with provisions for both parents to provide for and spend time with the child. Under Missouri law, a child has a right to frequent, continuing, and meaningful contact with both parents in most situations. Custody is determined in Family Court.

Guardianship is a court-ordered relationship where an adult is appointed by the court to care for a minor child ("ward") whose circumstances require it, and to make decisions about the child's education, support and maintenance. Parents are the natural guardians for their child and do not need to be appointed by a court. If necessary, the court may appoint a guardian to take care and control of the ward even though custody has been awarded to the parents. A person appointed as guardian must be suitable and qualified and is usually a close adult relative willing to serve. The guardian must always act in the best interest of the ward and make a report to the court at least annually. The guardianship of a minor child terminates when the child reaches 18 years of age. Guardianship is determined in Probate Court.