Your child will file a tax return in their own name for money earned from their own work. If their income is less than $12,550, they aren't required to file (unless they also have investment or unemployment income more than $2200), but they might want to file to get a refund of any withholding. You never include a child's income from working on a parent's return.
Filing a return in their own name does not, by itself, meant they can't be a dependent. You would still consider the factors listed in the other answers.
