The ALSAA aimed to identify and describe the comprehensive and unique profiles of autistic adults and compare them with adults without autism in Australia. These data were intended to support the development of approaches to improve the health and well-being of autistic adults. There were three participant groups: autistic adults, carers and family members of autistic adults, and a comparison group of adult community members who were not on the autism spectrum. Approximately 300 autistic adults (including 42 with informant reports), 100 carers and 150 non-autistic participants completed baseline surveys, beginning in 2015. Participants were followed up around two and a half years later. An additional 300 participants were included as a cross-sectional group at the second data collection from 2017 to 2021.