Low enrollment of Latino, African American, Native American, and Southeast Asian American students in science, technology, engineering, and math (STEM) classes, via advanced placement (AP) courses, remains a problem for high schools, and education leaders across the United States. More than just examining the factors behind this enrollment issue, we wanted to understand the focal factors underpinning success in AP courses of those few who do enroll. For that purpose, we grounded this case study on social cognitive theory's central variable of self-efficacy. We found that teacher facilitated experience plays a pivotal function in students' success in STEM education, more specifically, AP math.