Young children's challenging behavior can impact all aspects of the classroom environment, including relationships (peer-peer, student-teacher), learning, and safety. Positive Behavior Interventions and Supports (PBIS) is a program that focuses on supporting pro-social behaviors and preventing challenging behavior. PBIS begins with building a foundation of universal practices and creating a common language that teachers, children, and families can use to talk about behavior. The identification and defining of appropriate behavioral expectations and the systematic teaching of those behavioral expectations is paramount to preventing challenging behavior. This article describes the steps involved in identifying classroom behavioral expectations and the development of developmentally appropriate lesson plans to teach those behaviors to young children.