Can I claim my gf and her kids on taxes?

You can probably claim them as dependents.

However.......(Here is the biggie.....)

You CAN NOT claim them for the Earned Income Tax Credit, the Child Tax Credit and they do not qualify you for Head of Household as they are not related to you by blood or marriage.

So.....

If you put your relationship to them on your tax return as "Other" or "None", you should be OK.

But...

If you lied and put Son/Daughter or Niece/Nephew as your relationship, you going to have to write a pretty big check back to the IRS.

If you support your girlfriend and her children you file your return as single and can claim exemptions for them as "other relatives." If you married the gf the tax benefits would be a lot greater.

a qualifying relative is one who lives in your household the ENTIRE YEAR, does not earn the personal exemption for that year, you provide more than 50% of their support and they cannot be claimed on another tax return

if she and her children comply with these requirements you can claim them

You can claim them as dependents, but can't claim any child-related credits or file as head of household.

You'd better go get some professional tax help since you obviously don't know what you're doing.

if you provide over 50% of their support you can claim them

If she has no income and lives with you all year and so do the kids, yes.

If you are being audited, get a professional...