This paper extends the research on the Community of Inquiry (CoI) framework of understanding features of successful online learning to include the effects of the software used to support and facilitate it. This study examines how the Learning Management System (LMS) affords people the ability to take actions in an online course. A model is proposed to explain the effect of LMS affordances on the Community of Inquiry and on course satisfaction, and propose and test several hypotheses about their relationships. A pilot study found that while two common Learning Management Systems had different tools, faculty varied widely in their use and perception of the affordances of the tools. In the subsequent quantitative study, surveys were administered to 605 online students in a large Midwestern university. Regression analysis found that perceived LMS affordances predicted teaching, cognitive and social presence among students; in addition, satisfaction with the LMS predicted course satisfaction. (Contains 4 tables and 1 figure.)