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Can I claim my boyfriends son since I paid for his living expenses? His father did not work in 2017.

He is not my biological child.

Best answer by Coleen3

You can't claim him as your own child but possibly as a qualifying relative.

Do they live with you? Your relative must live at your residence all year or be on the list of “relatives who do not live with you” in Publication 501. About 30 types of relatives are on this list.
Do they make less than $4,050? Your relative cannot have a gross income of more than $4,050 and be claimed by you as a dependent.
Do you financially support them? You must provide more than half of your relative’s total support each year.
Are they a citizen or resident? The person must be a U.S. citizen, a U.S. national, a U.S. resident, or a resident of Canada or Mexico. Many people wonder if they can claim a foreign-exchange student who temporarily lives with them. The answer is maybe, but only if they meet this requirement.
Are you the only person claiming them as a dependent? You can’t claim someone who takes a personal exemption for himself or claims another dependent on his own tax form.
Are they filing a joint return? You cannot claim someone who is married and files a joint tax return. Say you support your married teen-aged son: If he files a joint return with his spouse, you can’t claim him as a dependent.

Employee

You can't claim him as your own child but possibly as a qualifying relative.

Do they live with you? Your relative must live at your residence all year or be on the list of “relatives who do not live with you” in Publication 501. About 30 types of relatives are on this list.
Do they make less than $4,050? Your relative cannot have a gross income of more than $4,050 and be claimed by you as a dependent.
Do you financially support them? You must provide more than half of your relative’s total support each year.
Are they a citizen or resident? The person must be a U.S. citizen, a U.S. national, a U.S. resident, or a resident of Canada or Mexico. Many people wonder if they can claim a foreign-exchange student who temporarily lives with them. The answer is maybe, but only if they meet this requirement.
Are you the only person claiming them as a dependent? You can’t claim someone who takes a personal exemption for himself or claims another dependent on his own tax form.
Are they filing a joint return? You cannot claim someone who is married and files a joint tax return. Say you support your married teen-aged son: If he files a joint return with his spouse, you can’t claim him as a dependent.