This study analyzes the online survey results of 788 students at W Cyber University to investigate the structural relationships among learners' sense of presence of the Community of Inquiry framework (Teaching, Cognitive, and Social Presence) and institutional support toward learner satisfaction by applying structural equation modeling. After satisfying the fitness of the measurement and the structural models, this study confirmed the direct effect of Teaching Presence, Cognitive Presence, and institutional support on learner satisfaction. Social Presence, however, did not show a significant causal relationship toward satisfaction, probably due to the lower level of learners' perception and needs for Social Presence in this study. These results suggest that online education should establish strong Teaching Presence with clear learning objectives and immediate feedback, and Cognitive Presence emphasizing on interactive, reflective learning activities to generate new knowledge. It was also confirmed that institutional support such as quality administrative assistance and institutional culture had a direct effect on learner satisfaction in a cyber university. In order to understand and improve learners' experiences in an online learning environment, research on the multiple components of the Community of Inquiry's presences, and how these components interact with other learning conditions (e.g. learners' characteristics) is suggested.