Group contingencies describe interventions in which a reward is delivered to a group of individuals based on meeting a predetermined target level of performance. Group contingencies have repeatedly been found to be effective in modifying student behavior. Not only are group contingences effective, but they also have several logistical advantages over individual contingencies. Namely, the delivery of a common consequence to a group of individuals increases efficiency, the use of peers as change agents increases positive peer pressure for appropriate behavior, group contingencies are flexible, and they allow access to a variety of reinforcers. Three different types of group contingencies are described. Finally, specific examples of group contingencies are provided. This includes the Good Behavior Game, Positive Peer Reporting, and Mystery Motivator.