The authors' main purpose in this article is to examine whether peer presence, measured by overall class attendance rate, has any significant effect on college students' academic performance. They use a rich dataset from an intermediate microeconomics course from the fall of 2008 to the spring of 2013 at a public university in Taiwan. The estimation results reveal a significant and negative effect of peer attendance on individual students' examination performance. This result suggests that potential distraction from peers dominates the beneficial effect of peer attendance. In addition, the subsample estimation shows that the presence of peers produces a negative effect on better-motivated students' examination performance. Hence, the beneficial effects of a typical mandatory attendance policy considered in prior literature must be reassessed.