The mental health and well-being of teachers is an issue of great policy concern. This is particularly true in England, where high workload and the associated stress is thought to be leading to a recruitment and retention crisis within the education profession. But do individuals who decide to leave teaching for another career actually see their well-being and mental health improve? We provide new evidence on this matter for individuals aged between 40 and 65, using the rich information gathered as part of the UK Biobank study. Our analysis shows that individuals who choose to leave teaching are somewhat happier in their work, but do not generally experience any improvement in their general well-being or mental health. We hence caution those middle-aged teachers who are thinking of leaving teaching that the grass may not necessarily be greener on the other side.