There is growing concern over the number of young children who display challenging behavior and preschool teachers are reporting children's challenging behavior as their greatest concern. Program-wide Positive Behavior Support (PWPBS) is a promising model for supporting appropriate behavior and decreasing challenging behavior in early childhood programs. Implementation in early childhood settings is relatively new and guidance on how to implement PWPBS in early childhood settings is growing. This article documents the implementation process for an early childhood program serving children from 6 weeks to 5 years of age, shares lessons learned and offers practical advice for getting started with PWPBS.