This chapter examines the role of sense of belonging among students of color in science, technology, engineering, and math (STEM) fields. Sense of belonging takes on heightened significance in environments that individuals experience as different, unfamiliar, or foreign, as well as in contexts where some individuals are likely to feel marginalized, unsupported, or unwelcomed. Turning attention to understanding the influence of sense of belonging in STEM fields is important for several reasons. Sense of belonging in STEM was also important for racial/ethnic minority students participating in summer or short-term research experiences for undergraduates. STEM leavers also underscored the importance of sense of belonging, or lack thereof, when discussing reasons for changing majors, changing institutions, or leaving higher education altogether. Belonging experiences seemed particularly meaningful for students who might otherwise have felt marginalized, unprepared for, or "out of place" in STEM fields such as people of color.