Some laws about receiving child support after the age of 18 include support continuing after 18 if the child has special needs or if the child is still in school, FindLaw notes. These laws may vary by state.
All states have established legal regulations that allow child support to end when the child reaches the age of majority, FindLaw notes. The age of majority is regulated under state law but means that when the child is no longer a minor and can make certain legal decisions on their own. In most states, this age is when the child turns 18 or when he graduates from high school, whichever happens first. In some states, this age is 21. Some states require a parent to continue paying child support after the age of 18 if he continues onto college or post-secondary school.
Some states have laws that allow the parents to enter into an agreement that obligates a parent to continue paying child support after the age of 18, Legal Zoom says. This circumstance is usually common if the child is mentally or physically disabled. As long as the contract is valid under the laws of the state, it can be enforced just as any other contract by filing a lawsuit.