Background Self-rated participation is a clinically relevant intervention outcome for people with mild intellectual disability. The aim of this systematic review was to analyse empirical studies that explored relationships between either environmental factors or individual characteristics and aspects of participation in young adults with mild intellectual disability. Method Four databases were used, 756 abstracts examined and 24 studies were evaluated in-depth. Results Four aspects of participation were found: involvement, perceptions of self, self-determination and psychological well-being. Reported environmental factors were: social support, choice opportunity, living conditions, school, work and leisure, attitudes, physical availability and society. Reported individual characteristics were adaptive and social skills. Conclusions There is a relative lack of studies of factors influencing self-rated participation and existing studies are difficult to compare because of disparity regarding approaches, conceptual frameworks, etc. For adequate interventions, it seems important to study how profiles of participation are influenced by different patterns of environmental factors and individual characteristics.