The only real requirement age-wise is that all of your baby teeth have to be out and replaced with adult teeth. So typically, 12 or 13 is the beginning age that people can start wearing Invisalign. If you have a younger child that could possibly benefit from it, there is a newer thing called Invisalign First, which is designed to deal with things like lost teeth. You could ask your dentist about that to see if your child could be a candidate for that. Teenagers and older tend to be the regular audience for Invisalign, if their teeth are ready for it.