The increasing frequency of international and intercultural communication has made English a top priority foreign language taught in Vietnam. Given that culture is inseparable from English language teaching, especially in the landscape of English as an international language (EIL), English teaching materials should integrate and reflect culture teaching perspectives under the EIL paradigm. The present study aimed at examining the extent to which the cultural contents in six English textbooks for the upper secondary level in Vietnam correspond with the EIL paradigm. A content analysis of these textbooks was conducted. The findings reveal signs of EIL paradigm influence in the set of investigated English textbooks. Firstly, the ‘source culture’ and the ‘international target culture’ appeared more frequently than the ‘target culture’. Secondly, the ‘international target culture’ covered a diversity of cultures in the world with a noticeable emphasis on ASEAN countries. The ‘interactional culture’ which is used to examine the reflection of source culture on other cultures is also found in a relatively large number of units. Finally, the ‘global culture’ is presented throughout the set of textbooks as topics of units.