One core aspect of learning a language is developing vocabulary, an endeavor that requires a structured and principled focus in the classroom. As the EFL textbook has a central position in the language learning classroom, it should have an important role to play in structuring vocabulary development. Yet, what guides decisions concerning the vocabulary content in textbooks has not been thoroughly studied. This paper presents an interview study with eight Swedish materials developers of frequently used EFL teaching materials aimed at school years 7-9. The results show that the materials developers focus primarily on providing engaging texts and base the vocabulary content on end users' opinions and their own intuition. The study also indicates that word lists are construed as a tool primarily for reading comprehension rather than for vocabulary learning. The study concludes that vocabulary research findings appear to have a limited impact on decisions about vocabulary content.