How do I know if children are my dependents if I am unmarried but am a parent/guardian to them along with my partner who is one of their birth parents?

[jackdesigns]

My partner and I are not married yet and file taxes separately. As a birth parent, he has been claiming them as his dependents. Having merged households over the past year and officially co-parenting with him, should I be claiming the kids as my dependents as well?

[SharonD007]

It depends. If your children meet the qualifying requirements of a qualifying child or a qualifying relative, then you can claim them as a dependent. Only one taxpayer can claim a child as a dependent.  

To determine if the individual is your qualifying child, the following questions must be true:

• The child must be related to you. 
• The child can’t be claimed as a dependent by someone else. 
• The child must be a U.S. citizen, resident alien, national, or a Canadian or Mexican resident. 
• If the child is married, they can’t file a joint return with their spouse. 
• The child must be under the age of 19 (or 24 for full-time students). 
  • No age limit for permanently and totally disabled children. 
• The child must have lived with you for more than half the year (exceptions apply). 
• The child didn't provide more than half of their own support for the year. 

If the individual doesn’t qualify as your qualifying child, you may be able to claim them as your qualifying relative. The following questions must be true:

• The individual can’t be claimed as a dependent by someone else. 
• The individual must be a U.S. citizen, resident alien, national, or a Canadian or Mexican resident. 
• If the individual is married, they can’t file a joint return with their spouse.
• The individual must live with you all year.
• The individual  can’t have made more than $5,050 in income in 2024.
• You must provide more than half of their total support for the year.

 Please review the TurboTax Help article Who can I claim as my dependent?

If you claim your children, review the TurboTax Guide to Filing As Head Of Household to determine if you can file using the Head of Household filing status.

[DoninGA]

If you are not legally married then each child can only be claimed on one tax return.  If you want to claim a child on your tax return and your partner claim the other child on their tax return, that is fine.