Managing how to finance a company is one vital factor for achieving a business’s potential. How to manage the cost of a business requires commercial comprehension in not only capital investments and expenses for administration, operation, production, sale, marketing, and so forth, but also the extrinsic determinants of “taxes and duties”. Doing business in Thailand requires substantive comprehension of various types of taxes and duties including income taxes and consumption taxes. This chapter discusses considerations regarding Thai taxes when doing business in Thailand.