Reflecting the neglect of childhood disability in social stratification research, there is a notable dearth of research on the mechanisms underpinning disability differentials in educational outcomes. Drawing on rich longitudinal data collected at 9, 13 and 17 years as part of Ireland’s ‘Growing Up in Ireland’ study, we look at the impact of special educational needs (SEN) identification in primary school on upper secondary outcomes. A bioecological framework and the Process–Person–Context–Time model allow us to understand how interactions with family, teachers, friends and school—as proximal processes—relate to early school leaving and post-school planned pathways after accounting for personal and context characteristics. Overall, young people identified at age 9 as having SEN are at increased risk of early school leaving and are more likely to plan to attend further education and training, rather than higher education. However, after accounting for proximal processes and personal and context variables, students identified at age 9 as having SEN are no longer distinct in terms of secondary attainment and post-school planning. Instead, these young people are more likely to experience forms of vulnerability that are important in shaping these outcomes. These key educational outcomes are strongly shaped by family and school-related factors—both proximal processes and context characteristics—suggesting that efforts to support retention and pathway planning should be underpinned by an ecological understanding of young people’s trajectories and the cumulative disadvantages they face.