Background: Despite an increase in inclusive studies in recent years, research on the views of the people with and without disabilities who have participated in these studies is scarce. The aim of this study was to explore the perceptions and views of advisors with intellectual disabilities and non-disabled researchers who collaborated together on a joint project to study transition to adulthood. Materials and Methods: Two questionnaires were devised, one for advisors and one for researchers; two focus groups were held with people with intellectual disabilities, three focus groups with researchers, and one focus group with all participants together. Thematic analysis was used for the data analysis. Results: The advisors valued this experience as an opportunity to learn new skills, freely express themselves on matters that affect them, and engage in a socially valued activity. The researchers considered that the participation of people with intellectual disabilities contributed to improving the quality of the research. Conclusions: The study provides a better understanding of inclusive research processes by taking into account participants' views.