QMCSO is an abbreviation for qualified medical child support order, which is an order made by a court or state administrative agency that an alternate beneficiary, such as a participant's child or stepchild, is entitled to be covered by the participant's group health plan.

Under the Employee Retirement Income Security Act (ERISA), a QMCSO is a medical child support order, i.e., a judgment, order, or decree under state domestic relations law or other relevant state law that provides for child support or health benefits coverage for the child of a group health plan participant. A medical child support order that can become a QMCSO, in turn, is required to establish or recognize an alternate beneficiary's right to receive the participant's benefits under the group health plan or to assign this right to receive group health plan benefits to an alternate beneficiary.

[Last updated in May of 2022 by the Wex Definitions Team]