For most people, getting married will reduce their income tax liability. You would have to file jointly or married filing separately. However, for some couples where both have income-primarily those who have similar amounts of income-it will slightly increase their tax liability. Filing separately will almost always result in more tax payable than filing jointly because a lot of beneficial deductions or tax attributes are not allowed to either of you.
Answered on Nov 17th, 2011 at 10:52 PM