Background: Increasingly, pupils on the autism spectrum are educated in inclusive mainstream classrooms. However, they often experience social isolation and bullying, and raising the awareness of autism in peers has been suggested as a remedy. Methods: In order to assess autism awareness in peers, autism-related questions were included in two large-scale surveys: the Kids Life and Times survey for 11-year olds and the Young Life and Times survey for 16-year olds; a total of n = 3353 children and young people completed the surveys. Results: Autism awareness was higher for the teenagers (80%) than for the younger children (50%). Many of the children knew someone with autism (50%) and generally reported positive and supportive attitudes. Self-reported prevalence of autism was 3.1% for teenagers and 2.7% for the younger children. Peers recognised bullying as a problem and were willing to help. Conclusions: Children and young people have good levels of awareness and knowledge about autism and reported positive attitudes towards peers with autism and are willing to help those who are bullied. A higher than expected number of children and young people self-reported being on the autism spectrum. These findings bode well for peer-mediated support strategies for inclusive education.