The transition from primary to high school can be a challenging process for students with autism spectrum disorder (ASD). During this time, research-based practices like home-school collaboration are crucial in facilitating a smoother transition. However, existing research indicates that the transition from primary to high school is a period of anxiety and reduced support for students with ASD and their families. This article describes the experiences of parents of students with ASD in regard to this transition and home-school collaboration. Semi-structured interviews were carried out with 15 parents of children with ASD who attended mainstream government high schools in metropolitan Sydney. Through content analysis, parents were found to have received varying levels of transition support. Their experiences of home-school collaboration were, however, generally positive. Overall, it is recommended that parents' knowledge of their children with ASD should be prioritised and utilised in transition planning. Findings also suggest that a greater implementation of practices including mandated transition planning and home-school collaboration in schools would contribute to more authentic inclusion of students with ASD.