Does Thailand have specific transfer pricing laws?

No, Thailand currently does not have any specific transfer pricing provisions under the Thai Revenue Code.
Until now the Revenue Department has relied on some general provisions in the Revenue Code, which authorize the assessment officers to adjust a transfer price based on an arm's length price and determine or recalculate a Thai resident company's taxable income when the transfer price used by that company and its foreign related party is either below or above an arm's length price.
In May 2015, a draft Act on Revenue Code Amendment that will add specific transfer pricing provision into the Revenue Code was approved by the Cabinet, and has been awaiting consideration and approval by the National Assembly of Thailand to become an applicable law since then. One of the key provisions of the draft Act requires transfer pricing disclosures to be made within 150 days from the year-end closing date (same deadline as corporate income tax returns). Failure to comply would result in a penalty not exceeding THB 400,000.