Despite posing challenges for teachers and students in English-medium instruction (EMI) contexts, materials are a relatively under-researched area of EMI. Our preliminary study takes a humanistic perspective to examine the extent of English-language material use, and faculty and student perceptions of materials used for EMI in Japan and China. Data in this concurrent mixed-methods research came from two selected-response and one open-ended questionnaire question, as well as interactions during interviews and focus groups with teaching staff and students. Although a wide range of English-language materials are available, many of them are not suitable for use by EFL, ESL and Anglophone students. There is also a lack of breadth of cultural content and of cultural perspectives on content in English-language materials. Therefore, although EMI aims to internationalize curricula, materials, which are usually sourced from Anglophone contexts, may have the effect of Westernizing the curriculum in EMI contexts.