Few evidence-based practices (EBPs), defined as the use of empirically supported research and clinical expertise for children with autism, have been successfully implemented and sustained in schools. This study examined the perspectives of school personnel (n = 39) on implementing a social engagement intervention for children with autism. Semi-structured interviews, informed by the Domitrovich and colleagues’ (2008) framework, were conducted. Participants were asked about: 1) school factors that affect the general implementation of EBPs; 2) their specific experiences implementing the social engagement intervention; and 3) barriers to and facilitators of implementing the social engagement intervention. Data were analyzed using an integrated approach. General (e.g., implementation process, leadership, support, staff) and intervention-specific (e.g., staff, barriers, facilitators) implementation themes were identified. These findings suggest that a variety of factors should be considered when implementing EBPs in schools and that implementing social engagement interventions for children with autism may require additional specific support for implementation.