Can I claim my girlfriend kids even though she has her father’s kids on child support. They lived under me this whole year

[xmasbaby0]

Provide more details.    You do not mention whether your GF has any income which would allow HER to claim her own children.  Since they are not your bio-children, if they lived with you all year, and you provided over half their support, you might be able to claim them as "qualified relatives" and get the $500 credit for other dependents.  But you cannot use them as qualified dependents to file as Head of Household, child tax credit or earned income credit, since they are not related to you.   If GF has less than $4700 of income --not counting Social Security -- you might be able to claim her for a $500 credit too.  That credit is not refundable---it reduces the tax you owe.

https://ttlc.intuit.com/questions/4499708-what-is-the-500-credit-for-other-dependents-family-tax-cre...

IRS interview to help determine who can be claimed:

https://www.irs.gov/help/ita/who-can-i-claim-as-a-dependent

https://ttlc.intuit.com/questions/3113432-who-can-i-claim-as-my-dependent  

[Opus 17]

They are not your biological children and you are not married?

You can only claim unrelated children as dependents if you meet all these tests.

a. No other taxpayer qualifies to claim them as dependents. 

b. They lived in your home all 365 days of the year.

c. You paid more than half their total financial support.

d. They have less than $4700 of taxable income.

This type of dependent will allow you a $500 credit, not the $2000 child tax credit, and not EITC, and not the child and dependent care credit, and not head of household filing status. 

If your girlfriend (their mother) is a taxpayer, then only she can claim them, based on your facts (because the children did not live with the other biological parent).  Your girlfriend is a taxpayer if she files a tax return, unless the only reason she files is to claim a refund of tax withholding and claims no other credits or deductions.  Generally, this means that if she does not work, and her taxable income is less than $13,850, then she does not have to file a tax return and does not count as a taxpayer.

[Hal_Al]

This reply says the same thing as the other two replies, just using different words.

Q. Can I claim my girlfriend kids even though she receives child support, from their father. They lived with me this whole year.

A. Yes, probably, but there are more rules to follow and you'll need to do the support calculation. 

The IRS has a worksheet that can be used to help with the support calculation. See: http://apps.irs.gov/app/vita/content/globalmedia/teacher/worksheet_for_determining_support_4012.pdf The support value of a home is the fair market rental value, divided by the number of occupants.

Although the amount of child support provided by the father is irrelevant if the mother wants to claim the children (qualifying child rules), it is not irrelevant for you (qualifying relative rules).  The child support counts as  support not provided by you, in the support calculation.

There are two types of dependents, "Qualifying Children"(QC) and Other ("Qualifying Relative" in IRS parlance even though they don't have to actually be related). There is no income limit for a QC but there is an age limit and student status test, a relationship test and a residence test. Only a QC qualifies a taxpayer for the Earned Income Credit and the Child Tax Credit. The Other dependent (qualifying relative) credit is worth (up to) $500 per dependent and is non-refundable.  That is, it can only be used to reduce an actual tax liability.

A person can still be a Qualifying relative dependent, if not a Qualifying Child, if he meets the 6 tests for claiming a dependent:

1. Closely Related OR live with the taxpayer ALL year
2. His/her gross taxable income for the year must be less than $4700 (2023) ($4400 for 2022).
3. The taxpayer must have provided more than 1/2 his support

In either case:

4. He must be a US citizen or resident of the US, Canada or Mexico
5. He must not file a joint return with his spouse or be claiming a dependent of his own
6. He must not be the qualifying child of another taxpayer*

He must have a US social security number or tax identification number (TIN)

*In addition to the above requirements, to claim your girlfriend's children, they must meet all of the above requirements and:

--- your girlfriend must not be required to file a return,
--- she does not file a return claiming the children