Project ImPACT is a parent-implemented intervention, focused on teaching social communication to toddlers and preschoolers with autism. The program can be used in an individual, group, or telehealth version and uses a blend of developmental and behavioral techniques. We found sufficient evidence to consider the original Project ImPACT as an established evidence-based intervention and to rate the telehealth version as promising. Parental satisfaction is consistently high in studies on the program. Several studies also reported a decrease in parental stress. The four main intervention targets of Project ImPACT are social engagement, communication, imitation, and play. The effect on the language and communication of young children with autism is the most robust. There is also some evidence for an effect on social engagement, imitation, play, and social skills in general. However, these findings are more mixed, possibly related to child characteristics, treatment fidelity, and differences in outcome measures. Given the large variability in outcomes, sample characteristics, and adaptations to the original intervention, more research is needed to further guide practical decisions.