This article examines the relationship between MBA students' performance and participation in two online environments: a synchronous forum (chat room) and an asynchronous forum (discussion board) at an Australian university. The "quality" and "quantity" of students' participation is used to predict their final examination and course grade performance outcomes. We find that the total "quality" of students' participation is positively related to final examination performance but the total "quantity" of students' participation is related to overall course performance. We also find that synchronous engagement with the course (combined "quality" and "quantity") drives these results and has twice the examination and grade impact relative to asynchronous course engagement. We conclude that encouraging high quality and frequent participation in both synchronous and asynchronous forums will help maximise students' performance.