This curriculum is based on the peaceable classroom model, which emphasizes cooperation, communication, appreciation of diversity, the healthy expression of feelings, responsible decision-making, and conflict resolution. This guide presents over 150 activities and tools to help middle school students learn to effectively handle the conflict that goes along with this developmental stage. It teaches students active listening, perspective taking, negotiation, and mediation skills. Based on the unique needs of middle school students and their teachers, the activities are cooperatively structured and presented for three levels (grades 6, 7, and 8). Through discussion, role playing, and journal writing, students broaden their definition of conflict, discover how conflicts escalate, explore connections between diversity and conflict, and learn how to de-escalate conflicts. Suggestions for infusing these activities into the standard middle school curriculum are included. The nine appendixes present gathering and closing activities; guidelines for role playing; instructional strategies; written tests; samples of conflict resolution projects; related resources; additional lessons for specific classroom issues; and a developmental overview of adolescents and conflict. (SM)