Corporate income tax filings
In short
Thai companies file a half-year and an annual corporate income tax return with the Revenue Department under the Revenue Code. Taxable profit is accounting profit adjusted for non-deductible items, and BOI-promoted companies apply the privileges granted in their certificate.
The half-year return is based on an estimate, and a materially understated estimate can attract a surcharge. Building the estimate from actual first-half performance rather than from last year's number avoids that.
Deductibility is decided on documentation as much as on principle. Expenses need to be substantiated, in the company's name, and connected to the business — the three tests that account for most audit adjustments.
What we need from you
- Draft or audited financial statements for the period
- Schedule of non-deductible and adjusted items
- BOI certificate and privilege details, where applicable
- Prior year return and any assessment correspondence
Watch out
Rates, reductions and SME thresholds are set by regulation and change. Verify current figures with the Revenue Department before relying on them.
Reviewed as of 2026-08-04. General guidance only, not case-specific advice and not a guarantee of outcome. Government fees, conditions and processing times are set by the responsible authority and can change. This site does not publish prices — please ask our staff.
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