Background: Social impairments characteristic of autism spectrum disorder (ASD) are evident in early childhood and worsen as the child matures. Though many interventions for young children exist, few specifically target social skills and involve caregivers. Aims: This pilot study examined PEERS® for Preschoolers, focusing on temporal change in child social skills, caregiver style, and family functioning in the context of a caregiver-assisted social skills intervention. This extension of the PEERS® program builds on the success of the intervention for older children, presenting skills in a developmentally appropriate manner to young autistic children and their caregivers. Methods and procedures: The present pilot study used a non-concurrent multiple baseline design to examine the above variables with 15 autistic children (Mage = 4.87, SD = 1.25; 11 boys). Children and caregivers participated in PEERS® for Preschoolers groups, with each group randomly assigned three different baseline periods (1.5, 2, or 2.5 weeks) before beginning. Outcomes and results: Simulation Modeling Analysis (SMA) revealed concurrent improvements in social and caregiving skills, with subsequent changes in family functioning occurring over the course of this 16-session intervention. Conclusions and implications: Future research will need to examine mechanisms of change in PEERS® for Preschoolers for children and caregivers. What this paper adds: There is a dearth of research that specifically examines social skills interventions for young autistic children that incorporates caregivers and examines family functioning as well. This paper is one of the first to evaluate the PEERS® for Preschoolers (P4P) intervention by: 1) exploring changes in child social skills, caregiver efficacy, and family functioning, and 2) analyzing the sequence of improvements in the aforementioned variables to measure systematic change. This pilot study presents results using appropriate methodology for a small sample size of children and caregivers. Results suggested concurrent improvements in social and caregiving skills and subsequent changes in family functioning. These can be built upon for further research on the PEERS® for Preschoolers intervention. This study supports PEERS® for Preschoolers as a feasible intervention that likely contributes to improvements for the child, caregiver in their relationship with their child and parenting styles in general, as well as functioning of the entire family. In sum, this work is essential to furthering the provision of a much needed service of social skills interventions for young autistic children.