Businesses operating in Thailand need to distinguish between expenses recorded in their financial statements and costs that can legally be deducted when calculating corporate income tax. An expense may be commercially genuine and properly recorded in the accounts but still be restricted or disallowed under Thailand’s tax rules.
Thailand’s Revenue Code identifies several categories of non-deductible expenditure, including personal costs, certain tax penalties, unsupported payments and most accounting provisions. Additional restrictions can apply to entertainment, passenger vehicles, charitable donations and payments between related companies in different countries.
For foreign-owned businesses, understanding these rules is particularly important because an incorrect deduction can increase taxable profits and lead to additional tax, penalties or surcharges.
Which Business Expenses Are Not Tax-Deductible in Thailand?
Section 65 Ter of Thailand’s Revenue Code sets out categories of expenditure that cannot be deducted when determining taxable profits. The precise treatment depends on the nature of the expense, the supporting evidence and any applicable exceptions.
Expense category | General tax treatment |
|---|---|
Personal or non-business costs | Generally disallowed if unrelated to the company's business activities. |
Corporate income tax | Not deductible when calculating taxable profits. |
Tax fines and surcharges | Generally non-deductible where covered by the applicable restrictions. |
Unsupported expenses | May be disallowed when the company cannot substantiate the expense or identify the recipient as required. |
Capital expenditure | Generally capitalized rather than deducted immediately, with depreciation potentially available. |
Excessive or unreasonable expenditure | May be restricted where the amount exceeds what is supportable under the relevant tax rules. |
Accounting provisions and reserves | Generally non-deductible unless a specific exception applies. |
Companies should not assume that every payment classified as an expense in their accounting system automatically qualifies for a tax deduction. Maintaining invoices, contracts, payment records and evidence of the business purpose can help support the treatment adopted in the tax return.
Repairs Versus Capital Improvements
The distinction between repairs and capital expenditure is another important consideration.
Routine maintenance that restores equipment or property to its existing operating condition may qualify as a deductible business expense. By contrast, expenditure that substantially improves an asset, increases its value or extends its useful life may need to be capitalized and depreciated over time.
The correct treatment depends on the work performed and the applicable tax rules, rather than simply the description used on an invoice.
Which Business Expenses Are Subject to Deduction Limits?
Some expenses are potentially deductible but are subject to specific ceilings, documentation requirements or eligibility conditions. Exceeding a limit can result in part of the expenditure being added back when calculating taxable income.
1. Entertainment and Hospitality
Qualifying business entertainment expenses are generally subject to a deduction limit based on 0.3% of gross revenue or paid-up capital, whichever is higher, with a maximum ceiling of THB 10 million, according to the supplied report.
The expenditure must have a legitimate business purpose and meet the relevant approval and recordkeeping requirements. Certain gifts connected with business entertainment are also subject to a reported limit of THB 2,000 per person per occasion.
Companies should retain receipts, details of attendees, the business purpose of the event and any required management approvals. Personal hospitality should not be treated as a business expense merely because it was paid using company funds.
2. Passenger Vehicle Costs
Thailand applies specific limits to deductions involving certain passenger vehicles.
According to the supplied article, depreciation for qualifying passenger vehicles is generally calculated using a maximum vehicle cost of THB 1 million. For example, if a company purchases a qualifying vehicle for THB 1.5 million, the depreciable amount for tax purposes may be restricted to the applicable THB 1 million ceiling.
Leasing costs for qualifying vehicles are also subject to reported limits of THB 36,000 per month or THB 1,200 per day, including VAT, depending on the applicable arrangement.
These restrictions may vary with vehicle classification and the nature of the business. Companies should verify whether an exception applies before calculating their deductions.
3. Charitable Donations
Donations do not automatically qualify for a full tax deduction simply because they support a charitable cause.
The supplied report describes general limits of 2% of net profits for qualifying public-benefit donations and a separate 2% limit for eligible education and sports donations, with possible enhanced deductions for certain approved contributions.
It also reports that, from January 1, 2026, donations covered by the new requirement to temples, qualifying charitable organisations, hospitals and educational institutions must be recorded through Thailand’s e-Donation system to qualify for deductions.
Because donation eligibility and documentation requirements can change, companies should confirm the rules applicable to the recipient and the date of the contribution before claiming a deduction.
Are Payments to Overseas Parent Companies Tax-Deductible?
Foreign-owned businesses in Thailand may be able to deduct legitimate payments to overseas related entities, including management fees, shared-service charges, interest and royalties. However, the fact that a payment has been made to a parent company does not automatically make it deductible.
The company must generally be able to demonstrate that the expense relates to its business, satisfies the relevant tax requirements and is supported by adequate documentation.
For example, if a Thai subsidiary pays its Singapore-based headquarters for regional accounting services, it should retain the service agreement, invoices, evidence of work performed and a reasonable explanation of how the fee was calculated or allocated.
The Thai Revenue Department may scrutinize payments where:
The services did not provide a demonstrable benefit to the Thai company.
The charges duplicate services already performed locally.
The expenditure relates primarily to the overseas parent’s own activities.
The amount charged cannot be adequately justified.
The company cannot produce sufficient records to support the transaction.
Interest on related-party loans and royalties for intellectual property may also qualify for deductions, subject to applicable requirements, including relevant arm’s-length pricing rules.
Withholding Tax and Transfer Pricing Considerations
Deductibility is only one part of the analysis. Cross-border payments may also trigger withholding tax obligations, and transfer pricing rules may apply to transactions between related entities.
A company should therefore assess the underlying transaction, supporting documentation, applicable treaty provisions and any relevant reporting requirements rather than assuming that an expense is compliant simply because it is recorded in the accounts.
Foreign branch offices also need to ensure that head-office expenses allocated to the Thai branch genuinely relate to the branch’s activities. Allocation methods should be reasonable, consistent and documented, and the same expenditure should not be deducted twice.
What Happens If the Thai Revenue Department Rejects an Expense?
When a deduction is disallowed, the amount may be added back to the company’s taxable profits. This can increase the tax payable for the relevant accounting period, and additional penalties or surcharges may apply depending on the circumstances.
Consider the following simplified example based on the figures in the supplied article.
Illustrative tax adjustment
Originally reported taxable profits
THB 10,000,000
Expense deduction disallowed
THB 2,000,000
Adjusted taxable profits
THB 12,000,000
Additional tax at 20%
THB 400,000
Illustration only. Assumes the standard 20% corporate income tax rate applies to the full adjustment and excludes penalties, surcharges and other tax considerations.
The Revenue Department may request invoices, contracts, accounting records, bank payment evidence and other documents supporting the deduction. If an assessment is issued, the company may have rights to object or appeal under the applicable procedures and deadlines.
Maintaining accurate records throughout the year is generally more effective than trying to reconstruct the commercial justification for transactions after an audit begins.
How Businesses Can Reduce Tax Compliance Risks
Companies operating in Thailand can strengthen their tax processes by reviewing expenses before filing their corporate income tax returns.
Practical steps include:
Separating personal expenditure from genuine business costs.
Keeping invoices, contracts and payment evidence for material expenses.
Reviewing capital expenditure and depreciation calculations.
Monitoring statutory limits on entertainment, vehicles and donations.
Documenting the commercial purpose of payments to related overseas companies.
Checking withholding tax and transfer pricing obligations on cross-border transactions.
Reviewing changes in tax rules and recordkeeping requirements.
For foreign-owned businesses, periodic financial and tax reviews can help identify unsupported deductions and documentation gaps before they become formal disputes. Business advisory services may help companies assess financial processes and identify areas requiring further compliance review.
Conclusion
Thailand’s rules on non-deductible and restricted business expenses make it important for companies to review both the purpose of their spending and the evidence supporting each deduction. Personal costs, unsupported payments, capital expenditure and certain accounting provisions require particular attention, while entertainment, vehicle costs, donations and cross-border payments may be subject to additional conditions.
For businesses with international operations, the challenge is not simply recording expenses accurately. It is ensuring that deductions are supported by the relevant tax rules, appropriate documentation and, where necessary, a defensible commercial rationale.