Many children with autism spectrum disorder (ASD) display elevated levels of challenging behaviors and decreased social engagement. Parent Child Interaction Therapy (PCIT) may help children with ASD increase rates at which they engage and interact with their caregivers. Existing barriers to treatment completion, including high attrition and travel time and costs, may be ameliorated by delivering PCIT virtually (iPCIT) and setting attainable mastery criteria. This study utilized a multiple baseline design across three caregiver-child dyads with ASD to determine whether an iPCIT protocol affected caregivers’ use of positive engagement skills, children’s engagement, and children’s challenging behaviors. Results demonstrated increased and improved caregiver-implemented engagement and behavior management practices with some improvements in child outcomes. These findings suggested that iPCIT is an effective treatment modality for teaching parents to increase and maintain their use of positive engagement skills across time. Without explicit instructions to avoid negative interaction behaviors, increases in positive engagement skills did not result in concomitant decreases in negative interaction behaviors. Increases in social engagement were observed for two children, but a decrease in engagement was observed in the third. Implications for future research and practice are discussed.