With the intent of better understanding how mentoring was established during the music student teaching experience, the purpose of this collective case study was to investigate the impact of a collaborative action research project on the cooperating teacher/student teacher relationship. Participants in this study were three cooperating teacher/student teacher pairs who worked collaboratively on an action research project, during which the author collected data before, during, and after implementation of the projects. The following themes emerged from the data: Cooperating Teacher Qualities (being welcoming, providing leadership/guidance, giving specific and positive feedback, showing confidence and trust in their student teacher), Student Teacher Qualities (inquisitiveness, taking initiative, showing respect, displaying gratitude, being prepared) and Increased Collaboration. The student teachers exhibited specific qualities that shaped their experience; the cooperating teachers appreciated these qualities in their student teachers and as a result, were more willing to share teaching responsibilities. Cooperating teachers and student teachers alike desired a personal connection with one another that would allow for an authentic, comfortable relationship. Participation in the action research project resulted in increased opportunities for collaboration between the cooperating teacher and student teacher, which led to a relationship that was more collegial in nature.