Using self-reported academic cheating from the classes of 1959 through 2002 at the three major United States military service academies (Air Force, Army, and Navy), we measure how peer cheating influences individual cheating behavior. We find higher levels of peer cheating result in a substantially increased probability that an individual will cheat. One additional college student who cheated in high school drives approximately 0.33 to 0.47 additional college students to cheat. One additional college cheater drives approximately 0.61 to 0.75 additional college students to cheat. These results imply, in equilibrium, the social multiplier for academic cheating is approximately three.