This study examines the effects that online collaborative note-taking has on student performance. The study draws on 10 weeks of data from 273 STEM university students who were collaborating in 61 groups. Group and individual learning were assessed weekly by evaluating the completeness of collaborative note-taking documents and subsequent individual assessments. Analysis suggested up to 23% of the variation in course performance could be attributed to between-group effects. Further, a series of 10 multilevel temporal models suggested no substantive effects in the first half of the course, though in the second half of the course, groups that co-created more complete course notes tended to exhibit improved average student performance. We speculate that the learning advantages afforded to student groups that produce more complete course notes may be delayed. This study adds to the growing body of research into the effects that collaboration has on student learning.