The transition from primary to secondary education (hereafter ‘school transition’) is a major ecological shift that poses considerable social, emotional, academic and organisational challenges. It is commonly assumed that this school transition is especially difficult for children with autism spectrum disorder, but that idea is mainly based on anecdotal evidence and requires systematic investigation. We describe change and continuity for children with autism spectrum disorder (N = 28, mean age = 11.29 years, mean full-scale IQ = 87.86) transitioning in mainstream education from primary to secondary school. Levels of psychopathology, adaptive functioning and peer victimisation were measured by parent, self and teacher report in the last year of primary school, and again after one term of secondary school. At follow-up, all participants were still in their secondary school, and there was no evidence for a marked escalation of difficulties during the transition. Instead, we observed high levels of psychopathology and maladaption at baseline which persisted across the transition and were in some cases under-recognised. By parent report, levels of bullying fell from primary to secondary school. Future research should investigate factors, such as school characteristics, that influence the move to secondary education in autism spectrum disorder, to inform the development of interventions to promote successful school transition.