Parent involvement in social skills training programs for autistic children has been associated with improvement in child and family functioning. However, limited research has explored parents’ treatment experiences, which may elucidate key therapeutic elements mediating long-term maintenance of outcomes. This study examines parent perspectives on the University of California, Los Angeles Program for the Education and Enrichment of Relational Skills (PEERS®) for Preschoolers, a group-based social skills intervention for young autistic children with social challenges. Twenty-four parents reported on outcomes and participated in semi-structured interviews 1–5 years after program completion. Inductive thematic analysis was used to categorize parent responses across four domains: Parenting behaviors, Child Outcomes, Parent Perspectives, and Challenges within Treatment. Results demonstrated an overall positive impact of PEERS® for Preschoolers, with children displaying increased social competence in peer interactions and parents emphasizing greater positivity, new parenting strategies, increased understanding, and more robust community support. Mixed methods analyses revealed that parents who endorsed continued use of social coaching skills, in particular priming and preparing their child for social interactions, showed greater improvements in long-term child functioning and parenting stress. Findings validate the efficacy of PEERS® for Preschoolers, while emphasizing the value of providing strengths-based coaching and social supports to parents participating in social skills treatment for children on the autism spectrum. Lay abstract Autistic children have social communication differences that can contribute to difficulties making and keeping friends, as well as poor mental health (e.g. anxiety, depression). Social skills training programs for preschoolers on the spectrum have been shown to increase social functioning and improve outcomes. Parent involvement in these programs is essential, as parents are able to use the intervention strategies outside of sessions. Teaching parents skills to help their children is also thought to reduce parenting stress through empowerment, knowledge, and social support. However, we still do not know much about how parents experience social skills treatments and whether there are specific parts that are especially helpful to them. This study examined parent perspectives on the University of California, Los Angeles Program for the Education and Enrichment of Relational Skills (PEERS®) for Preschoolers, an evidence-based, group social skills intervention for autistic young children who are struggling socially. Twenty-four parents reported on their child’s progress through questionnaires and participated in semi-structured interviews that asked about their experiences and perspectives 1–5 years after completing (PEERS®) for Preschoolers. Parents reported that their children displayed increased social skills and confidence after (PEERS®) for Preschoolers, while parents described feeling more positive, supported, and having greater understanding of their child and their development. Those parents who continued to use strategies taught in (PEERS®) for Preschoolers, particularly priming and preparing their child for social activities, showed greater improvements in long-term child outcomes and parenting stress. Overall, findings show that parents had a positive experience during and after PEERS® for Preschoolers, finding the program helpful in multiple ways to both their child and to themselves as a parent.