This reflective writing identified components that contribute to increased participation of international ESL in one online graduate course. All the factors identified in the analysis as conducive to greater engagement and elevated participation naturally fell into the three presences of Community of Inquiry (CoI). As such, a new theoretical framework titled CoIParticipation Model was created to reveal the underlying connection between CoI and participation. Findings drawn from the critical analysis indicate that online courses maintaining a good CoI can effectively promote ESL class participation, especially oral participation, by eliminating linguistic barriers, building a sense of group commitment, and creating a connected community of learners. Instructional implications and practical teaching tips for TESOL professionals incorporating the CoI-Participation Model in online teaching are discussed.