Southwest · OK
How to file Oklahoma sales tax
2026 due dates, filing frequencies, form STS-20002, and official filing resources.
- State return: STS-20002
- Monthly returns due: 20th of the month following the period
- Filing frequencies: Monthly, Semi-annual
When is Oklahoma sales tax due?
Monthly Oklahoma sales tax returns are due the 20th of the month following the period. When a due date lands on a weekend or federal holiday it moves to the next business day; the 2026 calendar on this page already applies that adjustment.
Oklahoma sales tax due dates for 2026
Every date below comes from the state's published deadline rule (dataset 2026.07.0) and is already moved to the next business day when it lands on a weekend or federal holiday. Your account's assigned filing frequency decides which table applies.
Monthly Oklahoma sales tax due dates
Rule: 20th of the month following the period.
| Period | Period ends | Return due |
|---|---|---|
| January 2026 | Jan 31, 2026 | Feb 20, 2026 |
| February 2026 | Feb 28, 2026 | Mar 20, 2026 |
| March 2026 | Mar 31, 2026 | Apr 20, 2026 |
| April 2026 | Apr 30, 2026 | May 20, 2026 |
| May 2026 | May 31, 2026 | Jun 22, 2026 (moved: 2026-06-20 falls on a Saturday) |
| June 2026 | Jun 30, 2026 | Jul 20, 2026 |
| July 2026 | Jul 31, 2026 | Aug 20, 2026 |
| August 2026 | Aug 31, 2026 | Sep 21, 2026 (moved: 2026-09-20 falls on a Sunday) |
| September 2026 | Sep 30, 2026 | Oct 20, 2026 |
| October 2026 | Oct 31, 2026 | Nov 20, 2026 |
| November 2026 | Nov 30, 2026 | Dec 21, 2026 (moved: 2026-12-20 falls on a Sunday) |
| December 2026 | Dec 31, 2026 | Jan 20, 2027 |
Semi-annual Oklahoma sales tax due dates
Rule: 20th of the month following the period (halves: due Jul 20 / Jan 20).
| Period | Period ends | Return due |
|---|---|---|
| January–June 2026 | Jun 30, 2026 | Jul 20, 2026 |
| July–December 2026 | Dec 31, 2026 | Jan 20, 2027 |
Oklahoma filing notes
No additional state-specific filing notes are recorded for this cadence set.
Return and form
The principal repository-tracked return is STS-20002. A paper channel exists, but the current form version and account eligibility still require confirmation.
Tracked form version: STS-20002-C May 2024 (periods beginning August 1, 2024 and after) + STS-20021 Revised 5-2024
Paper filing posture: accepted
Official Oklahoma filing resources
File Oklahoma sales tax from reviewed data, not spreadsheets
Prophit.ai tracks every Oklahoma due date above inside the return workspace, builds the period from your transaction data, and produces worksheet for portal entry that a reviewer approves before anything is submitted.
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Workflow support does not by itself establish registration, filing authority, credentials, agency acceptance, or tax advice. Confirm your assigned filing frequency with the state.
Oklahoma sales tax filing questions
When is Oklahoma sales tax due?
Monthly Oklahoma sales tax returns are due the 20th of the month following the period. When a due date lands on a weekend or federal holiday it moves to the next business day; the 2026 calendar on this page already applies that adjustment.
How often do you file sales tax in Oklahoma?
Oklahoma assigns a filing frequency to each account. The published cadences are monthly and semi-annual filing; the state assigns the frequency based on tax volume and notifies the account, so confirm the assigned basis before relying on a calendar.
What form is used to file Oklahoma sales tax?
The Oklahoma return tracked here is STS-20002. The principal repository-tracked return is STS-20002. A paper channel exists, but the current form version and account eligibility still require confirmation.
What happens if a Oklahoma due date falls on a weekend or holiday?
The due date moves to the next business day. In 2026, 3 of the Oklahoma due dates listed on this page are adjusted for a weekend or federal holiday; each adjusted date is marked in the calendar.
Can Oklahoma sales tax be filed on paper?
Paper filing posture tracked for Oklahoma: accepted. The principal repository-tracked return is STS-20002. A paper channel exists, but the current form version and account eligibility still require confirmation.