RESUMO
While inclusive education has achieved international importance, there is no valid instrument to measure teachers' competences in creating quality classrooms for diverse learners, which this study aims to remedy. Exploratory and confirmatory factor analyses with 975 pre-service teachers and 600 in-service teachers were used. Central to teachers' inclusive teaching competency is both beliefs and efficacy. Results show that teachers hold professional beliefs on student diversity, organized in four factors mapping unto axes of diversity (specifically ethnicity, disability, SES, and gender & sexuality). Teachers also hold beliefs on the responsibility of the educational field to create inclusion, organized in three factors: general school policy, initiatives geared specifically towards ethnic minority students, and initiatives for students with a disability. Furthermore, the results show five factors related to self-efficacy: noticing student diversity, enabling high-quality student-interactions, creating stimulating learning environments, collaborating with colleagues and diverse parents. The factorial structure and scale-scores are discussed for what they unveil of teachers' thinking about diversity in the classroom.