If you are paying or receiving child support under a Missouri order, you may wonder when the child support ends. The general rule is that child support ends when one of the following happens:
1. death of the child;
2. the child gets married;
3. the child becomes self-supporting (but only if the residential custodian has given up parental control of the child);
4. the child enters the military;
5. the child reaches 18 years of age AND is no longer a full time student AND is not so disabled that the court extends child support beyond the child's 18th birthday;
6. The child continues his or her education beyond high school (either with college, university of a trade school) and notifies you, and completes enough credit hours and gets good enough grades to have child support continue.
Child support ENDS on the child's 21st birthday unless the court finds the child is disabled.
The parent receiving child support is supposed to send a notice to you and the court when the child no longer qualifies to receive child support. If she doesn't do that you can send the notice to the court.
If she doesn't notify you that the child support has ended, she may have to pay you back - with interest.
The notification form (with instructions) is here.