It depends. In order to claim children as dependents, they must meet all of the following:
- They are related to you
- They aren't claimed as a dependent by someone else.
- They are a U.S. citizen, resident alien, national, or a Canadian or Mexican resident.
- They aren’t filing a joint return with their spouse.
- They are under the age of 19 (or 24 for full-time students).
- They live with you for more than half the year (exceptions apply).
For more detailed information please see (below) our guide on child dependents https://ttlc.intuit.com/replies/5187060