Supporting productive peer-to-peer interaction is a central challenge in online courses. Although cooperative learning research provides robust evidence for the positive outcomes of face-to-face cooperative learning (Johnson & Johnson, 1989), online modes of cooperative learning have provided mixed results. This study examines the effects of synchronous versus asynchronous interaction on students' sense of cooperation, belonging, and affect in online small-group discussions. Fifty-two undergraduate students were assigned to synchronous and asynchronous interaction conditions. The findings support prior research that asynchronous communication interferes with the relationship between cooperative goals and the outcomes of cooperation. Results inform theory and practice, by showing that asynchronous cooperative learning may not work as designed because the presence of cooperative goals do not predict cooperative outcomes.