Assessment in the large choral ensemble music classroom continues to be a widely examined topic among both practicing music educators and music education scholars. This instrumental case study (Stake, 1995) explored the lived experiences with assessment practices as reported by high school choir students and the choir teacher. The research site was a large, suburban, high school choral program in the Southeast United States. Research questions focused on participants’ beliefs about assessment, factors that influenced those beliefs such as the role of choir in the school curriculum and culture, and the challenges of assessing choral music students. Data generation methods included observational field notes, semi-structured interviews, focus group discussions, and collection of artifacts. Findings revealed that both musical and nonmusical assessment practices were used to evaluate student learning including participation and attendance-based assessments, a theory curriculum, and performance assessments. Students perceived all assessment practices, musical and nonmusical, to be in support of what they viewed as the primary goal of the choral program, ensemble achievement. That choir participation was positively perceived to be more like an activity and less like an academic class appeared to be a core belief at ATHS, and one that should be further examined in assessment discussions in music education.