This study focused on the analysis of the presentation of sources of culture in a series of English Textbooks used in Thailand and their presentation in the receptive skills and productive skills of language learning. It was revealed that source culture or Thai culture and international culture or culture of the foreign countries where English is used as a second or foreign language were presented in each series of textbooks in a much smaller proportion when compared to the target culture or the culture of America or Britain that accounted for almost half of the total units analysed. It was also shown that more than half of the units analysed were presented in receptive skills that show the target culture and less than half in productive skills that show the source culture. The results of this study provide implications for authors, publishers, and educational institutions on how sources of culture should be treated in English textbooks to better prepare Thai students for a wider range of international communicative settings.