New England · MA
How to file Massachusetts sales tax
2026 due dates, filing frequencies, form ST-9, and official filing resources.
- State return: ST-9
- Monthly returns due: 30 days after the period end (30th of the following month)
- Filing frequencies: Monthly, Quarterly, Annual
When is Massachusetts sales tax due?
Monthly Massachusetts sales tax returns are due the 30 days after the period end (30th of the following month). Quarterly returns are due the 30 days after the quarter end (~Apr 30 / Jul 30 / Oct 30 / Jan 30). 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.
Massachusetts 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 Massachusetts sales tax due dates
Rule: 30 days after the period end (30th of the following month). This cadence is flagged for manual review against the state source before relying on it.
| Period | Period ends | Return due |
|---|---|---|
| January 2026 | Jan 31, 2026 | Mar 2, 2026 (moved: 2026-02-28 falls on a Saturday) |
| February 2026 | Feb 28, 2026 | Mar 30, 2026 |
| March 2026 | Mar 31, 2026 | Apr 30, 2026 |
| April 2026 | Apr 30, 2026 | Jun 1, 2026 (moved: 2026-05-30 falls on a Saturday) |
| May 2026 | May 31, 2026 | Jun 30, 2026 |
| June 2026 | Jun 30, 2026 | Jul 30, 2026 |
| July 2026 | Jul 31, 2026 | Aug 31, 2026 (moved: 2026-08-30 falls on a Sunday) |
| August 2026 | Aug 31, 2026 | Sep 30, 2026 |
| September 2026 | Sep 30, 2026 | Oct 30, 2026 |
| October 2026 | Oct 31, 2026 | Nov 30, 2026 |
| November 2026 | Nov 30, 2026 | Dec 30, 2026 |
| December 2026 | Dec 31, 2026 | Feb 1, 2027 (moved: 2027-01-30 falls on a Saturday) |
- MGL c.62C §16(h) requires filing within 30 days of the period end; DOR publishes this as the 30th of the following month. The February date (no 30th) is clamped to month-end — DOR's exact published date was not verifiable (mass.gov blocked).
Quarterly Massachusetts sales tax due dates
Rule: 30 days after the quarter end (~Apr 30 / Jul 30 / Oct 30 / Jan 30). This cadence is flagged for manual review against the state source before relying on it.
| Period | Period ends | Return due |
|---|---|---|
| Q1 2026 | Mar 31, 2026 | Apr 30, 2026 |
| Q2 2026 | Jun 30, 2026 | Jul 30, 2026 |
| Q3 2026 | Sep 30, 2026 | Oct 30, 2026 |
| Q4 2026 | Dec 31, 2026 | Feb 1, 2027 (moved: 2027-01-30 falls on a Saturday) |
- DOR-published quarterly dates were not verifiable (mass.gov blocked); statutory rule is within 30 days of period end.
Annual Massachusetts sales tax due dates
Rule: ~January 30 following the calendar year. This cadence is flagged for manual review against the state source before relying on it.
| Period | Period ends | Return due |
|---|---|---|
| Calendar year 2026 | Dec 31, 2026 | Feb 1, 2027 (moved: 2027-01-30 falls on a Saturday) |
- DOR-published annual date was not verifiable (mass.gov blocked); statutory rule is within 30 days of period end.
Massachusetts filing notes
- Filers over $150,000 prior-year liability owe an advance payment by the 25th of the last month of each period (MGL c.62C §16B) (info only).
Return and form
The principal repository-tracked return is ST-9. The reviewed filing posture requires electronic filing rather than a mailed paper return.
Tracked form version: Filed online via MassTaxConnect
Paper filing posture: not accepted
Official Massachusetts filing resources
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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.
Massachusetts sales tax filing questions
When is Massachusetts sales tax due?
Monthly Massachusetts sales tax returns are due the 30 days after the period end (30th of the following month). Quarterly returns are due the 30 days after the quarter end (~Apr 30 / Jul 30 / Oct 30 / Jan 30). 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 Massachusetts?
Massachusetts assigns a filing frequency to each account. The published cadences are monthly, quarterly and 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 Massachusetts sales tax?
The Massachusetts return tracked here is ST-9. The principal repository-tracked return is ST-9. The reviewed filing posture requires electronic filing rather than a mailed paper return.
What happens if a Massachusetts due date falls on a weekend or holiday?
The due date moves to the next business day. In 2026, 6 of the Massachusetts due dates listed on this page are adjusted for a weekend or federal holiday; each adjusted date is marked in the calendar.
Can Massachusetts sales tax be filed on paper?
Paper filing posture tracked for Massachusetts: not accepted. The principal repository-tracked return is ST-9. The reviewed filing posture requires electronic filing rather than a mailed paper return.