Can I Claim My Girlfriend (16k income) As Dependent (100k my salary)

If your girlfriend has lived with you all of the calender year as a member of your household, her gross income is less than $3,500, and you’ve provided more than half of her total support during that calender year, you could claim her as a dependent on your tax return.

To determine if you pay for more than half of her support, see IRS Pub. 501, p. 16 - Support Test: IRS Publication 501, Exemptions, Standard Deduction, and Filing Information

Each dependent you claim on your 2008 tax return reduces your income by up to $3,500 (2009: $3,650)

If your girlfriend files a tax return, she would have to answer “yes” to the question “Are you being claimed as a dependent on anyone’s tax return?”  

Note: You can’t claim her as a dependent if living together is in violation of your local law. Generally, you may not claim a married person as a dependent if they file a joint return with their spouse. Also, to claim someone as a dependent, that person must be a U.S. citizen, U.S. resident alien, U.S. national or resident of Canada or Mexico for some part of the year. There is an exception to this rule for certain adopted children.