Early intervention is widely recommended for young children with autism spectrum disorder, but the effectiveness of interventions when implemented in inclusive preschool settings needs to be considered. To this end, we identified 16 studies that provided early intervention to children with autism spectrum disorder who were attending inclusive preschools. Effectiveness studies, that is, studies evaluating interventions that were implemented under real-world conditions, were targeted, provided they met the pre-determined inclusion criteria. Included studies were summarized in terms of (a) participant characteristics, (b) intervention procedures, (c) procedures for training teachers, (d) study design, (e) outcomes, (f) study quality, and (g) social validity. A range of intervention procedures were implemented, and positive outcomes for children and/or teachers were reported in most studies. However, methodological limitations were identified for most of the included studies, indicating the need for additional higher-quality research. Still, the present review suggests that teachers may be able to effectively deliver early intervention to young children with autism spectrum disorder in inclusive preschool settings.