This paper seeks to evaluate the effects of peer misbehavior in the classroom on student learning outcomes--namely, if there is any truth behind the old saying that “one bad apple ruins the bunch”. Using experimental data, I show that there is a strong initial relationship between the level of misbehavior in a given classroom and performance on a mathematics evaluation; however, the inclusion of lagged peer achievement in the model causes most of that relationship to be absorbed away, suggesting that the bulk of peer effects stem more from the academic performance of other students than from their behavior.