The Convention between Thailand and the Democratic Socialist Republic of Sri Lanka for the Avoidance of Double Taxation and the Prevention of Fiscal Evasion with respect to Taxes on Income was signed on 14th December 1988 and the instruments of ratification were exchanged on 12th March 1990.
Under Article 28, this Convention Shall apply in Thailand :
1. In respect of taxes withheld at source, on amounts paid or remitted on or after 1st January 1991,
2. In respect of other taxes on income, for taxable years or accounting periods beginning on or after 1st January 1991.