Your filing status for the entire year is determined by your marital status on December 31. If your divorce is not legally final by December 31, you are still considered married for that tax year and must file either jointly or separately — not as single. If your divorce is finalized by December 31 (even December 31), you file as single (or head of household if you have a qualifying dependent) for that full year. A legal separation decree recognized by your state may allow you to file as single in some cases. Divorce timing can have significant tax implications — consider consulting a CPA when finalizing your divorce to understand the impact on your filing status and tax bill.