A systematic literature review was undertaken to ascertain the prevalence of self-harm and suicidal behaviour in children and young people under 18 years old with a diagnosis of autism spectrum disorder (ASD), with or without an intellectual disability. There was variation in the reported prevalence rates but results suggested that rates of both self-harm and suicidal behaviour may be elevated in ASD compared to the general population. This is in keeping with literature relating to autistic adults but in contrast to conclusions of a previous systematic review. This review highlights the need for further research to explore the experience of self-harm and suicidal behaviour in autistic children and young people.