The study discussed here provides a test of media naturalness and channel expansion theories’ predictions in the context of university online learning. Data was collected from undergraduate students at the middle and end of a long semester in which the students took an introductory course in management information systems. Approximately half of the students took the course face-to-face, and the other half online. As predicted based on media naturalness theory, perceived communication ambiguity and cognitive effort were higher in the online than in the face-to-face condition. As a result, grades were significantly higher in the face-to-face than the online condition at the middle of the semester. Consistently with predictions based on channel expansion theory, the difference between grades obtained at the middle of the semester disappeared at the end of the semester.