The article presents the construction and validation process of a questionnaire designed to study student teachers' beliefs about cultural diversity. The study, beyond highlighting the complexity involved in the study of beliefs, emphasises their relevance in implementing inclusive educational processes that guarantee the right to a good education for all. The questionnaire was administered to 1464 students from the different Teacher Education specialties. The results show that the instrument has a satisfactory internal consistency and is structured in seven components that largely correspond to the theoretical proposals used as the basis for constructing the questionnaire. The actions and analyses performed in the process of elaborating this inventory represent an advance compared to other similar studies in this line of research. From a methodological point of view, they provide detailed information about the questionnaire's psychometric characteristics, reliability and validity, with particular emphasis on the empirical data stemming from its application. From a conceptual point of view, the study incorporates beliefs related to different theoretical models of attention to cultural diversity, as well as their possible practical derivations at different levels of specificity.