Periods of being NEET (not in education, employment or training) can have long-term consequences for individuals’ future job opportunities, earnings, psycho-social well-being and health, all with high societal costs. Therefore, policy-makers across Europe seek interventions that successfully reduce NEET numbers. Drawing on a longitudinal qualitative study in London, this paper explores the processes and mechanisms that contribute to young people becoming NEET after leaving education.Through analysis of 53 young NEETs’ accounts of their school and transition experiences, we draw upon Bronfenbrenner’s ecological systems theory to explore the multitude of factors and structures of disadvantage that might have contributed to these young people’s marginalisation in education and employment. We discuss how unfulfilled support needs, a lack of career advice and socio-economic disadvantage can lead to educational disengagement, dropping out and, ultimately, becoming NEET. While many of these issues were presented as personal difficulties, in this article we reject the individualisation of the ‘NEET problem’. Instead, we argue that negative school experiences need to be understood in the context of structural conditions, including funding cuts in education and support services, transformations in the labour market and socio-economic deprivation.