C Corporation Tax Deadlines in Massachusetts
Federal and state filing dates, extensions, and estimate schedules for 2026.
Massachusetts filing deadline
Calendar-year due date follows federal timing for corporations.
Due: Apr 15, 2026
Extension: Oct 15, 2026
Form: State C-corporation return
Estimated payments
Estimated payment dates: Apr 15, 2026, Jun 15, 2026, Sep 15, 2026, Dec 15, 2026.
Due: Apr 15, 2026
FAQ
Does Massachusetts require C Corporation estimated payments?
Estimated payments are scheduled for Apr 15, 2026, Jun 15, 2026, Sep 15, 2026, Dec 15, 2026.
Where can I file Massachusetts C Corporation taxes?
Use Massachusetts Department of Revenue resources at https://www.mass.gov/orgs/massachusetts-department-of-revenue for forms and filing instructions.