Yes. You can claim your grandson if all these requirements are met:
- 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).
- No age limit for permanently and totally disabled children.
- They live with you for more than half the year (exceptions apply).
If you need to add a Dependents in TurboTax Online, here's what you do:
1. Open your return in TurboTax, if you aren't already in it. (To do this, sign in to TurboTax and click the Take me to my return button.)
2. Search for personal information and then click the "Jump to" link in the search results.
3. Click through the interview until "Your children and others you support" screen (See the attached screenshot below. Click to enlarge.)
4. Follow the onscreen instructions to Add, Remove (Trash Can) or Review (edit) a dependent.