There is a prevailing need for social skills interventions that staff in public schools can deliver effectively to children with autism spectrum disorder (ASD). The present study leveraged partnerships among three large urban school districts and researchers at academic institutions to design and evaluate a social skills intervention, Remaking Recess (RR). In RR, members of the research team coached school personnel on strategies to increase peer engagement and social networking during unstructured times (i.e., recess or lunch). A three-site, randomized trial enrolled 80 children with ASD in 69 general education classrooms, grades K-5, in 35 public schools across three large urban districts. Children in RR were more included in peer social networks at follow up than children in the wait-list group based on peer sociometric ratings, F(1,118) = 1.97, p = 0.05. While there was no main effect of the intervention on peer joint engagement, children spent less time in solitude during recess in RR than in the wait-list group, F(1,76) = 4.01, p = 0.049. School personnel could implement the intervention and found it easy to use in a school setting. These results suggest that a personnel-facilitated intervention holds promise when it comes to changing school social environments and improving social outcomes for children with ASD.