This article delves into the issue of incorporating sociolinguistic aspects of language and culture into the current primary English textbooks in Vietnam. The authors first provide an overview of primary English teaching in the Vietnamese setting and then evaluate the current primary English textbooks in relation to the objectives of foreign language teaching and learning proposed by Vietnam's Ministry of Education and Training for the time period 2008-2020. The evaluation focuses on four main sociolinguistic aspects: teaching approach, bilingualism, language variations, and intercultural communication reflected in the primary English textbooks. The evaluation findings indicate that the textbook design follows communicative language teaching. However, English variations and cross-cultural knowledge are still limited in the textbook design. Although some signs of bilingualism are recognized in the teachers' books, it is not clear whether bilingualism or double monolingualism is encouraged by the textbook writers. In order to improve sociolinguistic understanding among young learners, the authors recommend cooperation among teachers, textbook writers, and policymakers.