The number of young people who are not in education, employment or training (NEET) is a key indicator on the state of youth labour markets and opportunities for young people more generally. However, it is a diverse group as people can be NEET for many reasons, and so understanding the importance of these reasons is crucial for targeting policy responses. This paper looks at data on young people between the age of 16 and 29 in the UK between 1975 and 2015, and highlights which characteristics are associated with a higher chance of being NEET and how the importance of these drivers has changed over time. We show that the overall NEET rate has fallen considerably since the 1980s, but has remained largely the same since 2000. Since the 1980s, the reduction in school leavers leaving with few or no qualifications, fewer young people having children and improvements in the chances for young women to work alongside childcare responsibilities have all put a downward pressure on NEET rates. However, penalties for women with childcare are still large, while an increase in the incidence of mental ill health has recently acted in the opposite direction.