From recent field and museum collections, new localities and range extensions of 47 taxa (28 species and 19 subspecies) of tiger beetles within various provinces of Thailand are reported. Therates rugulosus W. Horn, 1900 is reliably recorded for the first time in Thailand. The list of the tiger beetles of Thailand now has 146 taxa, including 35 endemics (28 species, 7 subspecies) and 27 near-endemics (24 species, 3 subspecies). The endemics represent 24% of the total species diversity, but together with near-endemics, it rises to 42.5%. Northern Thailand has the highest species diversity and the greatest endemism of tiger beetles in the country.