Sex education is critical for the development of healthy sexual identity and relationships. However, students with intellectual disability and/or on the autism spectrum often receive less holistic sex education in comparison to their neurotypical counterparts. A scoping review was undertaken to determine parents', teachers' and students' perspectives, attitudes and experiences related to sex education for high school-aged students with intellectual disability and/or on the autism spectrum. Findings revealed that only a few studies consulted students themselves, while most sought only parents' and teachers' perspectives. Teachers and parents had generally positive attitudes towards sex education for students with intellectual disability and/or on the autism spectrum. However, teachers' beliefs may prevent them from delivering sex education as intended. Furthermore, parents reported a lack of confidence in discussing sexuality with their children. Well-designed, disability-inclusive education programmes that prioritise safety, assertiveness and self-determination can support positive outcomes. Removing barriers to sex education in schools, and learning from students with intellectual disability and/or on the autism spectrum what they think could improve things for themselves and peers, is key to supporting them with their needs.