If my child turns 18 and decides to drop out of school because he is failing, do I still have to pay support. If he continues until the end of the year, and then does not graduate, because he failed required classes, but still lives at home, do I still have to pay support at the end of the scholl year? What if he does or does not have a job, does this effect the answer?

We can't answer those questions since they are usually spelled out in your support agreement. Generally support continue until 18 or when they finish schooling.

And in many states you will need to back to court to get the support payments terminated no matter what age your child is.

I agree, this is hard to say because each child support order is different. It all depends on what your specific order says. Although, as the other poster said, child support is often paid until they turn 18, as they are no longer considered a child, they are "of age" and considered adults.

The best thing is to read over your support order and see if it specifies, if not, you'll need to contact the lawyer who handled this, or you may have to contact the court to get clarification. Don't assume you'll still have to pay... double check so you won't be out money that you're not required to give.

As noted any back support will have to be paid, and in or out of school it is paid till at least 18, if they continue in school after 18, then it is more the if, depending on the exact terms of the written agreement