MOTIVATION: The transition from adolescence to adulthood encompasses key social changes. NEET status (ot in ducation, mployment or raining) during this period disrupts this transition and alters an adolescent's life course. This is of particular concern in South Africa, a middle-income country with one of the world's highest rates of youth unemployment. PURPOSE: The pathway to becoming NEET emerges over time by accumulating risks in early life and adolescence. Early-life adversities can increase the probability of events associated with becoming NEET. We aim to identify early-life and adolescent predictors of events associated with becoming NEET, as well as predictors of NEET status itself. METHODS AND APPROACH: We analyse four rounds of longitudinal data from a sample of 1,174 adolescents growing up in peri-urban KwaZulu-Natal, South Africa. Using a socioecological life-course model, we create two overlapping analytic cohorts and two NEET vulnerability indices to evaluate whether risks for vulnerability in schooling (early outcomes) are similar to those affecting post-schooling education and labour-market outcomes (later outcomes). We use a linear probability model to analyse the relationship between the vulnerability indices and the range of risk factors in the socioecological life-course model. FINDINGS: A strong predictor of both NEET vulnerability indices includes reporting feeling hopeless about the future. Other significant predictors include behavioural factors (getting pregnant or impregnating someone during adolescence, and drinking alcohol before age 16), family structure (residing with one's biological mother in early adolescence was protective) and demographics (age). POLICY IMPLICATIONS: By deepening our understanding of how individual and contextual characteristics shape the transition into productive adulthood through a life-course approach, we can identify possible early intervention points lost once young people become NEET.