The current investigation tested the efficacy of the Extended Class Exchange Program (ECEP) in reducing prejudicial attitudes. Three hundred and twenty-two 3rd and 4th grade students from both Israeli–Jewish and Israeli–Palestinian schools in the ethnically mixed city of Jaffa were randomly assigned to either intervention or control classes. Members of the intervention classes engaged in ECEP's activities, whereas members of the control classes engaged in a social–emotional learning program. The program's outcomes were measured a week before, immediately after, and 15 months following termination.