In order to explore the factors that inform the occupational identity development of in-service music educators and to compare the identities of in-service teachers with those of preservice music educators as examined in previous research, the purposes of this study were to examine the reported occupational identity of in-service secondary music educators and identify the interpersonal interactions and activities that help form occupational identity. A stratified random sample of secondary music teachers (N = 300) completed a questionnaire based on previous research. Participants reported a majority of integrated (view of self and perceived view of others) professional roles, although participants believed themselves to be musicians more than they felt others believed them to be. Participants reported positive interactions with music students and other music educators and that directing ensembles and attending music conferences were the most positive experiences. Participants who reported positive relationships with other music educators and music students were likely to develop an educator identity. External musician identity was predicted by relationships with other teachers as well as with students outside of music. Participants with positive administration relationships were less likely to exhibit an internal musician identity. As teachers move from preservice to in-service, their musician identities may transform from being relatively integrated to becoming more differentiated. (Contains 4 tables and 1 figure.)