Per IRS Publication 17 Your Federal Income Tax (For Individuals), page 24:
If your spouse died in 2017, you can use married filing jointly as your filing status for 2017 if you otherwise qualify to use that status. The year of death is the last year for which you can file jointly with your deceased spouse. See Married Filing Jointly, earlier.
You may be eligible to use qualifying widow(er) as your filing status for 2 years following the year your spouse died. For example, if your spouse died in 2016, and you haven't remarried, you may be able to use this filing status for 2017 and 2018.
This filing status entitles you to use joint return tax rates and the highest standard deduction amount (if you don't itemize deductions). It doesn't entitle you to file a joint return.
Eligibility rules. You are eligible to file your 2017 return as a qualifying widow(er) if you meet all of the following tests.
- You were entitled to file a joint return with your spouse for the year your spouse died. It doesn't matter whether you actually filed a joint return.
- Your spouse died in 2015 or 2016 and you didn't remarry before the end of 2017.
- You have a child or stepchild (not a foster child) whom you can claim as a dependent or could claim as a dependent except that, for 2017:
This child lived in your home all year, except for temporary absences. See Temporary absences, earlier, under Head of Household. There are also exceptions for a child who was born or died during the year, and for a kidnapped child. You paid more than half the cost of keeping up a home for the year. See Keeping Up a Home, earlier, under Head of Household.
- The child had gross income of $4,050 or more,
- The child filed a joint return, or
- You could be claimed as a dependent on someone else’s return.
If the child isn't claimed as your dependent on Form 1040 or Form 1040A, line 6c, enter the child's name on line 4 of the form you are filing. If you don’t enter the name, it will take us longer to process your return.
After the two years, you may be able to file as Head of Household, if you qualify.