Persons with intellectual disabilities have a higher risk of mental and physical ill health, more non-communicable diseases, and shorter life expectancy than the general population. These disparities stem partly from unhealthy lifestyle habits and partly from unequal access to health-promoting services, while tailored, person-centred lifestyle interventions remain insufficient. Although persons with intellectual disabilities often express a desire to participate in research concerning their health and well-being, they are frequently excluded from health research. A central premise of the ACCESS project is therefore that persons with intellectual disabilities should not merely participate in research but in collaboration with researchers. The lived experiences and perspectives of persons with intellectual disabilities are essential for developing knowledge that is relevant, accessible, and grounded in the realities of their everyday lives. The overall aim of the ACCESS project is to enhance access to person-centred lifestyle counselling for persons with intellectual disabilities, including the development of a digital screening tool that supports participation and self-determination in lifestyle habits assessments. At the same time, the project seeks to contribute to methodological development by demonstrating how research can be conducted in genuine collaboration with persons with intellectual disabilities, representing an important step toward more inclusive and equitable health research. Therefore, a competence group comprising persons with intellectual disabilities is actively involved in the ACCESS project to ensure participation, equality, and a holistic perspective. The competence group contributes to the design, implementation, as well as interpretation of the results and findings, thereby serving as co-creators in the research process. In this way, the project becomes a shared learning journey in which academic and experiential knowledge meet on equal terms. The process with the competence group, as well as the researchers’ and the competence group’s experiences from this process, will be the focus of the presentation.