Previous research has shown that children and adolescents on different CP trajectories are exposed to a higher risk of being not in education employment or training (NEET) in young adulthood/adulthood. However, there has not been much research on factors that may mediate the association between CP trajectories and NEET status at age 20. In the present study, we investigated the role of school experience at age 14 years in mediating the association between CP trajectory group defined from age 4 to 13, namely Early-Onset Persistent (EOP), Adolescent-Onset (AO) and Childhood-Limited (CL), and Low (L) and NEET status at age 20. Using G-computation, we estimated the natural direct and indirect effects of CP trajectory group on NEET using data from ALSPAC. We found that school experience mediates the relationship between EOP trajectory and NEET status at age 20. The impact of attrition on these results was also investigated via imputation of missing values under the assumption of missing at random. These findings highlight the role of schools in potentially minimising the risk of becoming NEET in high-risk youth.