In this article, action research is explored as a process for instructor reflection, professional learning and collaboration. The context for the professional learning was the teaching of graduate level education courses in which action research, in conjunction with a cohort-based, collaboratory approach to learning, was used to facilitate students' design and enactment of site-based action research. Action research was used as a research methodology by course instructors who reflected on the design of the course and their pedagogical practices in order to engage in continuous quality improvement. The collaboration took place over a two-year period in which the instructors taught multiple online sections of the course. Using action research to collectively deepen understanding about teaching action research proved to be a valuable reflective experience for the instructors and continues to inform ongoing instructional design processes and the development of future research agendas related to instructor collaboration and action research.