The deadline to file state taxes in Oklahoma generally aligns with the federal tax deadline, which is typically on April 15 each year. If April 15 falls on a weekend or a holiday, the deadline may be adjusted to the next business day. It is important for taxpayers to be aware that extensions can be requested, allowing for an additional six months to file, which would push the deadline to October 15. However, it is essential to note that any taxes owed must still be paid by the original due date to avoid penalties and interest. For the most current information regarding tax deadlines, including any possible changes or updates, it is advisable to visit the official Oklahoma Tax Commission website.