Can I claim F1 visa student as a dependent?
She is my wife's niece living with us and has Fi viza. My wife and I are US citizen.
We support most of her expenses. Does she qualify as our dependent?

No, an F1 student is exempt from residency for 5-years, and a dependent must be a resident. Read: Your U.S. Tax Return: Requirements for claiming a dependent (http://taxipay.blogspot.com/2008/03/requirements-for-claiming-dependent.html)