In general, costs not incurred for the production of taxable income are not deductible for Thai tax purposes. Specific non-deductible costs include:

• Expenses not supported by sufficient documentation are not deductible;
• Expenses where the recipient is not identifiable are not deductible;
• Capital expenditures are not deductible;
• Damages recoverable under an insurance or contract of indemnity are non-deductible;
• Allocations to reserves are not deductible;
• Fines and penalties are not deductible;
• Unaccrued expenditures from a previous period are not deductible;
• Entertainment expenses exceeding the higher of 0.3% of gross revenue in an accounting period or the amount of paid-up capital at the close of the period, with a hard cap of THB 10 million, are not deductible; and
• Donations to social enterprises, i.e., entities that do not share profits, made through the Revenue Department’s e-donation system until 31 December 2023, are deductible up to 2% of the net profit of companies, taking into account other donations for charities/public benefits.