Summary: US research reveals a significant relationship between university STEM (science, technology, engineering or mathematics) disciplines and the development of students’ religious or spiritual characteristics and interfaith competencies. Yet, in the UK, as university applications for STEM disciplines hit a record high, little research has considered belief diversity (defined as the diversity of religious, spiritual or non-religious traditions, positions or worldviews, including unbelief) in STEM, despite disparities in the number of STEM student applicants from religious backgrounds. To promote meaningful university STEM opportunities for underrepresented belief groups, we must better understand how to foster STEM environments inclusive of belief diversity. This project will achieve this by addressing four research questions: How do UK STEM students’ lived experiences of belief intersect with their identities as scientists? How do UK STEM students’ attitudes and behaviours in relation to belief diversity change during one academic year in comparison to US STEM students? How