The troubling negative effects of music performance anxiety (MPA) have remained less investigated under ensemble settings and with undergraduate non-music majors than under solo settings with music majors and professional musicians. This study examined the experience and prevalence of music performance anxiety in ensemble rehearsal and concert settings in 166 undergraduate non-music majors, 108 undergraduate music majors, 4 undeclared undergraduates, 9 graduate non-music majors, and 14 graduate music majors. The participants (instrumentalists and vocalists) were drawn from 10 Mid-Atlantic colleges and universities. The Kenny Music Performance Anxiety Inventory Revised (K-MPAI-R; Kenny, 2009) was administered within the last six weeks of the semester. Students reported the full range of cognitive, somatic, affective, and behavioral symptoms of MPA, with cognitive symptoms most frequently reported. The factor structure of the K-MPAI-R was found to be stable with those factor structures previously established by Kenny using elite professional musicians and tertiary-level music students. The results of a standard multiple regression conducted to identify unique predictors of MPA indicated that although depression, being an instrumentalist, being female, and having had a music performance breakdown, all made significant contributions to K-MPAI-R scores, and depression made the strongest unique contribution (beta = .42, p < 0.001). Greater self-efficacy (as indicated by higher scores on confidence statements in the K-MPAI-R) was correlated with lower MPA under both concert (r = .49, p < 0.0005) and rehearsal settings (r = .52, p < 0.0005). Students with higher depression indicator scores exhibited higher MPA than students with lower depression indicator scores (WT = 31.40, p < 0.001). Music performance breakdowns occurred more often during solos than ensemble performances and memory lapse (16.3% of all students) was cited as the leading cause of music performance breakdowns. Overall, MPA and depression indicator scores for the sample were high compared with other groups that had been previously evaluated with the K-MPAI-R and the same depression screen. Instructors should therefore be sensitive to the possibility that ensemble musicians may experience significant negative effects of MPA during both concerts and rehearsals, and apprise themselves of evidence-based treatment options and coping strategies available for MPA.