Double Tax Agreement (DTA) and Thailand

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อัปเดตล่าสุดเมื่อ 5 กันยายน 2569

เอ double tax agreement (อนุสัญญาภาษีซ้อน, a DTA, double taxation treaty หรือ tax convention) is a treaty between Thailand and another country that allocates the right to tax each type of income between them and provides relief where both would otherwise tax the same money. Thailand has agreements with more than 60 countries. For a foreigner living in Thailand the treaty decides whether a pension, salary, dividend or rent from home is taxable here, there or both, and how tax already paid abroad is credited on the Thai return.

What a treaty does and how it is applied

Allocation. Each agreement defines residence, gives a tie-breaker (permanent home, centre of vital interests, habitual abode, nationality) for a person resident in both states, and then deals with income by class: employment income is generally taxed where the work is done; business profits only where there is a permanent establishment; dividends, interest and royalties may be taxed at source at a reduced rate, commonly 10% or 15%; and pensions are dealt with differently from treaty to treaty, with government service pensions usually taxable only by the paying state.

Relief. Most of Thailand’s agreements use the credit method: the country of residence taxes the income and allows a credit for the tax paid at source, up to the amount of its own tax. The result is that the taxpayer pays the higher of the two rates, not both. A few articles use exemption instead. The treaty prevails over the Revenue Code where the two conflict, but it never creates a tax that domestic law does not impose.

Using a DTA as a resident of Thailand

Since the 2024 change to the taxation of รายได้จากแหล่งต่างประเทศ, treaties matter to ordinary expatriates. A tax resident who remits a foreign pension or dividend declares it on the personal income tax return and claims the foreign tax as a credit, attaching the foreign assessment or withholding certificate, or cites the article that gives the other state the exclusive right. Nothing is automatic: relief is applied only when claimed and documented.

Two illustrations. A British state or private pension is generally taxable in Thailand when remitted, because the UK agreement has no article giving relief for private pensions, with credit for any UK tax paid. A US social security benefit is taxable only in the United States under the US agreement and stays outside the Thai return. Thai residents who need to prove their status abroad obtain form R.O. 22 from the Revenue Department.

What a DTA does not do

A treaty does not make foreign income exempt in Thailand; it only prevents the same income being taxed twice in full. A resident who paid no tax at home, for example on income that the home country does not tax non-residents on, gets no credit and pays the full Thai rate. It does not change the 180-day residency test or the remittance rule, and it does not exist for countries with which Thailand has no agreement.

Nor does a DTA settle immigration or reporting. Banks exchange account information under the Common Reporting Standard regardless of treaties, and the วีซ่า LTR exemption for remitted foreign income comes from a Royal Decree, not from any treaty. The common mistake is to assume that because tax was paid at home nothing needs to be filed in Thailand: the income must still be declared and the credit claimed on the return.

คำถามที่พบบ่อย

ดูเพิ่มเติม: Tax resident, Foreign-sourced income, Tax identification number, วีซ่า LTR, foreign income remittance tax in 2026 และ ภาษีเงินได้บุคคลธรรมดาในประเทศไทย.