Challenging behaviors are linked to negative long-term developmental outcomes for young children with disabilities and remain a primary focus of service delivery for many early intervention practitioners and families. Positive Behavior Interventions and Supports (PBIS) is a tiered prevention framework that recommends evidence-based positive behavior support (PBS) strategies to effectively address young children's challenging behaviors and promote prosocial skills. However, there is limited research investigating the feasibility of a PBIS approach in Part C early intervention settings, which employ a family-centered approach to serve an increasingly culturally and linguistically heterogeneous population of young children and their families. This article presents findings from a convergent mixed methods study aiming to understand the impact of PBIS approach components implemented in an early intervention context (PBIS-EI) to support diverse families in addressing children's challenging behaviors at home. EI practitioners' implementation of PBS strategies is measured over time and practitioner experiences with supporting parents' use of PBS strategies are explored via qualitative interviews. Findings show increases in EI practitioner confidence and implementation of strategies, as well as practitioner-reported experiences. Implications for practice and future research are discussed.