You can't file jointly with your girlfriend, since you're...

can I claim my live in girlfriend and our live in son as head of household? Can I claim head of household, claim them as dependents and file jointly with my girlfriend.

posted

You can't file jointly with your girlfriend, since you're not legally married. You may be able to claim her as a dependent, if her income was under $4050 in 2016. You should be able to claim your son as a dependent and file as head of household. However, you'll also have to meet the other requirements below.

https://turbotax.intuit.com/tax-tools/tax-tips/General-Tax-Tips/Guide-to-Filing-Taxes-as-Head-of-Hou...