School readiness is important to a positive start and success in school but children with Autism Spectrum Disorder (ASD) are at risk of not being school-ready. This study aimed to explore parent and therapist perspectives on school readiness skills of children with ASD and factors impacting on a positive mainstream school experience. A mixed methods design was used. Key findings were that school readiness depends on child and school factors, with social skills the most important child factor. The child’s experience was largely reliant on teacher and education assistant attitudes and highlighted a need for further training and support. This study identified areas of focus for early intervention as well as school-aged intervention and the need for collaborative practice.