- AIM: This study aimed to determine the developmental trajectories of social participation, by level of gross motor function and intellectual disability, in a Dutch population of individuals with cerebral palsy (CP) aged 1 to 24 years. METHOD: As part of the Pediatric Rehabilitation Research in the Netherlands (PERRIN+), 424 individuals with CP (261 males, 163 females; mean age [SD] 9y 6mo [6y 2mo]; Gross Motor Function Classification [GMFCS] levels I-V [50% level I]; 87% with spastic CP; 26% with intellectual disability) were longitudinally followed for up to 4 years between 2002 and 2007. Social participation was assessed with the Vineland Adaptive Behavior Scales survey. Effects of age, GMFCS level and intellectual disability were analysed using multilevel modelling. RESULTS: The developmental trajectories for individuals in GMFCS levels I to IV did not significantly differ from each other. For individuals without intellectual disability, the degree of social participation increased with age and stabilized at about 18 years. These individuals reached social participation levels similar to typically developing individuals. The trajectories were significantly less favourable for individuals in GMFCS level V and individuals with intellectual disability. INTERPRETATION: Intellectual disability is more distinctive for the development of social participation than GMFCS level. The developmental trajectories will support individuals with CP and their families in setting realistic goals and professionals in optimizing the choice of interventions at an early age.