The purpose of this social constructivist inquiry was to examine the experiences of three elementary music teachers in a collaborative teacher study group (CTSG). CTSG members, each from a different school district, met seven times to discuss elementary music student collaboration by analyzing video from their classrooms. Using interview and meeting transcripts, the researcher investigated how the CTSG member’ perceptions were affected by group interactions. Research questions were as follows: How do the participants describe their experience in the CTSG? How has the focus on collaboration in the CTSG changed their teaching practice? What can these music teachers tell other music educators about collaboration? Participants indicated the CTSG experience was effective professional development that sup- ported learning and remedied isolation. Participants gained confidence through the opportunity to share teaching expertise. However, the CTSG was not a satisfactory substitute for meaningful collaboration with colleagues in participants’ own districts. Three positive elements of the CTSG were the way the group collectively generated knowledge about music classroom collaboration, the way the group engaged in systematic analysis of music classroom video, and the way a protocol organized group discussion. The lack of overt disagreement in the group may have been a negative, indicating a possible avoidance of difficult topics. The CTSG collectively constructed three group-labeled "principles of collaboration": (a) Collaboration facilitates student self-expression and independence; (b) Students who are collaborating share goals. The teacher allows space for or guides students in creating productive student- student interactions; and (c) A teacher collaborating with her students facilitates their movement toward a shared goal. Teacher provides necessary background skills, creates student buy-in for the goal, and then fades away to allow students to take ownership.