You better be a good girl and hurry it up! April 15th is the deadline. Ok, seriously, if you can't file your tax return by April 15th, then you can get an automatic four-month extension of the filing deadline. About six million taxpayers request extensions each year. Just complete Form 4868, Application for Automatic Extension of Time to File U.S. Individual Income Tax Return, and file it with the IRS by April 15. You then have until August 15 to file your return without incurring late filing penalties.