The purpose of this study was to investigate the experiences of four preservice music teachers as leaders of adult chamber ensembles. Through examination of these teachers' reflections, we sought to answer the following questions: (a) What impact does leading an adult chamber ensemble have on preservice teachers' perceptions of their instructional behaviors? (b) Which specific instructional behaviors do preservice teachers focus upon when teaching adult learners? (c) How might preservice teachers project their experience teaching adult learners in a community music program to future experiences teaching in formal school settings? Four undergraduate music education majors at a large Midwestern university school of music in the USA participated in this study. Each participant served as a staff member for the university-sponsored New Horizons Band, teaching a weekly, 30-minute small ensemble rehearsal for eight consecutive weeks. Participant responses were examined four ways: (a) responses to a pre-questionnaire, (b) video diary entries, (c) interview transcript, and (d) responses to a post-questionnaire. Preservice teachers' credited their experiences leading New Horizons chamber groups for their perceived development and mastery of specific instructional behaviors. Implications for music education include the need to engage preservice teachers' in authentic teaching experiences, promoting transfer to future instructional settings.