Teacher education is constantly being renewed in response to continuous social, economic and technological changes. In 2008, teacher education in Iceland was extended from a three-year to a five-year master's degree program and this significantly increased the number of students at the master's level. To respond to these changes, 3 university-based teacher educators organized collaborative supervisory meetings for 18 master's students during the school years 2012-2014. We used self-study methodology to analyze our progress and inspire our development as supervisors. The goal was to gain a better understanding of how we learn together in collaborative supervision and to develop, adapt, and change our teaching and learning practices. Data included reflective notes and journals, recordings of students' and supervisors' meetings, e-mails, tickets out of class, and material from Moodle. Constant analysis of data was conducted with personal reflection and collective discussion, using theories to scrutinize data. Our findings show that, by working together on supervisory issues, we expanded our resources, strengthened our collaboration and trust, developed our professional identities, and improved our collective supervisory efficacy. We discovered that self-study provided an in-between space for us to explore cultures, roles, and visions as we collaboratively contested, defined and recreated our roles as supervisors.