Domestic car sales in August jumped 27.7% from a year earlier to 86,780 units, after a 25.7% increase in July, the Federation of Thai Industries said on Wednesday.
Sales were lifted by stronger economic growth and higher state and private investment as well as farm prices, the FTI said.
Auto exports in August fell 0.38% from a year earlier, after July's 0.15% increase.
Thailand is a regional vehicle production and export base for the world's top automobile manufacturers.