Recent research has shown that the presence of peers can increase individual output both in the lab and the field. This paper tests for negative side effects of such peer settings. We investigate whether peer settings are particularly prone to cheating even if they do not provide additional monetary benefits of cheating. Participants in our real-effort experiment had the opportunity to cheat when declaring their output levels. Although cheating did not have different monetary consequences when working alone than when working in the presence of a peer, we find that cheating is a more severe problem in peer settings.(JEL J20, J30, M50) * We thank settings. Hence, we are not primarily interested in productivity spillovers between low and high productive workers, but focus on the question whether it, on average, pays for employers to rely on peer settings instead of letting employees work alone.2. The motives underlying such social comparisons are self-evaluation, self-improvement, and self-enhancement (Gibbons and Buunk 1999). 11. Dai, Galeotti, andVilleval (2017) show that cheating behavior in the lab is related to cheating in the field. Furthermore, Herbst and Mas (2015) find that peer effects in the lab and in the field are comparable in size.