Considered the opposite of tattling, "Tootling" is a positive peer-reporting procedure in which students report their classmates' positive prosocial behavior instead of inappropriate behavior and employs other well-established behavior analytic principles. This study examined the effects of Tootling on students' behavior in three general-education high school classrooms. Students wrote and then submitted tootles into a marked container. Teachers recorded the number of tootles on publicly posted progress charts, and read a sample of tootles at the end of the class period. An interdependent group contingency procedure was used along with a class goal of the number of tootles needed to earn the class a reward. An A-B-A-B withdrawal design with follow-up found decreases in classwide disruptive behavior and increases in academically engaged behavior across classrooms. Results suggest that Tootling can provide high school teachers a method for positively reinforcing students' prosocial behavior, and function as a preventative measure against disruptive behavior. Issues related to social validity and directions for future research are discussed.