Try to make this short. Can my wife (permanent resident alien, aka green card holder) and I (US citizen) claim her children who are here in the US on F1 student visa's as dependents on our joint tax return? They have lived here for over 3 years and we fully support them (room, board, tuition, etc.).
Or, if we are not able to claim them for the deduction, can we list them as dependents for other purposes (lower in-state college tuition, etc)?
From IRS Publication 501:
"You can't claim a person as a dependent unless that person is a U.S. citizen, a U.S. resident alien, a U.S. national, or a resident of Canada or Mexico."
As F-1 visa holders and in the US for only three years, they are not US Resident Aliens yet.
You didn't say which country they are from. If they are not a "a U.S. national, or a resident of Canada or Mexico", no, they can not be claimed as dependents on your federal income tax return.
https://www.irs.gov/publications/p501#en_US_2024_publink1000196863
Do they have ITIN's or Social Security numbers?
IRS interview to help determine who can be claimed:
https://www.irs.gov/help/ita/who-can-i-claim-as-a-dependent
From IRS Publication 501:
"You can't claim a person as a dependent unless that person is a U.S. citizen, a U.S. resident alien, a U.S. national, or a resident of Canada or Mexico."
As F-1 visa holders and in the US for only three years, they are not US Resident Aliens yet.
You didn't say which country they are from. If they are not a "a U.S. national, or a resident of Canada or Mexico", no, they can not be claimed as dependents on your federal income tax return.
https://www.irs.gov/publications/p501#en_US_2024_publink1000196863