Paying Foreign Suppliers from Thailand: Withholding Tax Basics
<p>If your Thai company pays fees, royalties, interest, or service charges to a supplier based overseas, Thai law requires you to deduct a percentage of that payment and hand it to the Revenue Department before the money leaves the country. This is withholding tax on foreign payments, and it catches a lot of small business owners off guard. Miss it and you face penalties, back-taxes, and potentially a blocked transaction. This guide walks you through the basics in plain language so you know what to expect before you send that next international transfer.</p> <h2>What Is Withholding Tax on Foreign Payments?</h2> <p>Withholding tax (WHT) in this context means your Thai company acts as a tax collector on behalf of the Thai Revenue Department. Instead of paying a foreign supplier the full invoice amount, you deduct the applicable tax, pay the supplier the remainder, and then remit the deducted amount to the Revenue Department using a form called the Por Ngor Dor 54. The deadline is the seventh day of the month following the payment.</p> <p>The logic is straightforward: Thailand has the right to tax certain types of income that originate here, even when the recipient is a foreign company. Rather than chasing overseas entities for tax, the Revenue Department puts the obligation on the Thai payer. If you fail to withhold and remit correctly, the liability falls entirely on your company, not the foreign supplier.</p> <h2>Which Types of Payments Trigger the Tax?</h2> <p>Not every overseas payment is subject to WHT. The type of income matters enormously. The categories most commonly encountered by small businesses and foreign-owned Thai companies include dividends paid to foreign shareholders, interest on loans from overseas lenders, royalties for the use of intellectual property, and fees for services where the work is performed outside Thailand.</p> <p>The standard domestic rate under Thai law is typically 15 percent for dividends, interest, and royalties paid to foreign companies, though the exact rate can vary depending on the nature of the payment and whether a tax treaty applies. Fees for services performed entirely outside Thailand are generally not subject to WHT under domestic rules, but this is an area where the facts matter. If any part of the work takes place in Thailand, the picture changes, and you should take professional advice before assuming no tax is due.</p> <h2>What Is a Double Tax Agreement and Why Does It Matter?</h2> <p>Thailand has signed Double Tax Agreements (DTAs) with more than 60 countries, including the UK, Germany, Japan, Australia, Singapore, and the United States. A DTA is a treaty between two governments that decides which country gets to tax specific types of cross-border income, and at what rate. For businesses making payments to foreign suppliers, DTAs are important because they can reduce or eliminate the standard Thai withholding tax rate.</p> <p>For example, Thai domestic law may impose a 15 percent rate on royalties paid to a foreign company. If that company is resident in a country that has a DTA with Thailand, the treaty rate for royalties might be 5 or 10 percent instead. The difference goes straight back into your cash flow, which is worth paying attention to when you are making regular payments to overseas partners.</p> <h2>How to Claim Treaty Relief in Practice</h2> <p>Claiming DTA relief is not automatic. The foreign supplier must provide you with a certificate of tax residency issued by the tax authority in their home country confirming they are a tax resident there. This document is your evidence that the lower treaty rate legitimately applies. Without it, you are expected to withhold at the full domestic rate.</p> <p>You should request this certificate before or at the time of payment, not afterwards. Thai authorities can challenge treaty claims made without proper documentation at the time of payment. Once you have the certificate, keep it on file for audit purposes and attach a copy to the relevant Por Ngor Dor 54 filing. The certificate needs to be current, typically covering the tax year in question, and some countries issue them annually, so this is something to manage on an ongoing basis if you have regular overseas payments.</p> <h2>Common Mistakes That Create Problems</h2> <p>One of the most frequent errors is assuming that because a foreign supplier is a large, well-known company it is somehow exempt from Thai WHT rules. The obligation sits with the Thai payer regardless of the size or reputation of the overseas recipient. Another common mistake is treating all service payments as automatically exempt because the supplier works abroad. The characterisation of income matters, and a payment described as a service fee on an invoice might actually qualify as a royalty under Thai law if it involves the use of software, a brand, or technical know-how.</p> <p>Businesses also run into difficulty when they gross up payments, meaning they absorb the WHT cost themselves rather than deducting it from the supplier's payment. Grossing up is permissible in some situations but it affects the calculation of the tax due and needs to be done correctly. Getting this wrong means you have both underpaid the tax and misrepresented the transaction in your accounts.</p> <h2>Practical Steps Before You Make the Payment</h2> <p>Before transferring funds to any foreign supplier, run through a short checklist. First, identify what type of income the payment represents under Thai tax law, not just how the invoice describes it. Second, check whether Thailand has a DTA with the supplier's country and what rate applies to this category of income. Third, request a tax residency certificate from the supplier if you intend to apply a reduced treaty rate. Fourth, calculate the correct WHT amount, prepare the Por Ngor Dor 54 form, and make sure you have the funds to remit to the Revenue Department by the due date. Finally, keep all documentation together in one place because WHT transactions are one of the areas Revenue auditors examine closely.</p> <p>These steps sound straightforward but the classification of income and the interaction between domestic law and treaty provisions can be genuinely complex. If you are unsure whether a payment triggers WHT, what rate applies, or how to document a treaty claim, speaking to an accountant familiar with Thai Revenue Department practice before you make the transfer is far cheaper than dealing with an assessment after the fact.</p>