Can I claim my 21 yr old daughter if she's not a full time student?

Yes, you can claim your daughter as a qualifying relative dependent. Dependents can be Qualifying Child or Qualifying Relative. Your daughter doesn't meet the requirements to be claimed as a qualifying child, (since she is over the age of 19 and not a full time student- see the requirement below ) but she meets the requirements to be claimed as a Qualifying relative.

Qualifying child:

• 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).

Qualifying relative:

• They don't have to be related to you (despite the name).
• 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 lived with you the entire year.
• They made less than $4,050 in 2017.
• You provided more than half of their financial support. More info

When you add someone as a dependent, we'll ask a series of questions to make sure you can claim them.