At what age is child support terminated in Alabama ?

When the child reaches the age of majority, 19, or later if the child is in high school or attending college or a trade program or post-secondary program past the age of majority, or is disabled.
Alabama recognizes two grounds for the continuation of support beyond the child’s reaching the age of 19. The first is for the payment of the expenses of college, and the second is for continuation of support for a disabled child if the disability continues into adulthood.

College support is pursuant to a case called Ex Parte Bayliss, 550 S.2d 986 (Ala. 1989). The key consideration in dealing with Bayliss support is that it has to be applied for before the child reaches the age of 19. If the child has already reached the age of 19 before Bayliss support is requested, courts have believed in the past that they lack the authority to award college support. The expenses included in Bayliss support are tuition, books, room and board, and necessary fees.
Info from divorcelaw.com
Support for a disabled child is pursuant to a case called Ex parte Brewington.[82] The Brewington court quoted with approval a court in New Jersey: “Children who are unable to care for themselves because of their minority are no less entitled to the court's solicitude when they continue to suffer, after they have attained their majority, from a physical or mental disability which continues to render them incapable of self-support. Normal instincts of humanity and plain common sense would seem to dictate that in such cases the statutory obligation of the parent should not automatically terminate at [the age of majority], should continue until the need no longer exists.”[83]