The purpose of this study was to identify distinguishing characteristics of action research within the Action Research Special Interest Group of the American Educational Research Association. The authors sought to delineate the foundational framework endorsed by this community. The study was conducted during January-April 2012 and employed an emergent simultaneous mixed-methods design utilizing Delphi and learning circles methodologies. The findings include 30 distinguishing characteristics of action research practiced within this knowledge community. The discussion addresses the challenges associated with defining action research, specific definitional issues, and prospects for opening dialogical spaces within which action researchers co-create knowledge. Potential implications for action research include: constructing boundaries of conceptual frameworks in action research; fostering coherence across action research studies; contributing to quality and rigor in critiquing action research; and supporting deeper dialogue on the established boundaries of action research frameworks.