If you need to change or amend an accepted 2019 Oklahoma State Income Tax Return, you have until July 17, 2023, to do it.
This date is in coordination with the Internal Revenue Service (IRS), which limits the amount of time you have to file an amended return to within three years from the original filing deadline.
An amended return can be filed in Oklahoma in two easy steps. First, download and Complete Form 511 (residents) or 511NR (nonresidents and part-year residents) for the appropriate tax year. Then, mail form 511 or 511NR to the address listed on the form.
