Teaching is understood to be a highly stressful profession. In England, workload, high-stakes accountability policies and pupil behaviour are often cited as stressors that contribute to teachers' decisions to leave posts in the state-funded sector. Many of these teachers leave state teaching to take jobs in private schools, but very little is known about the nature of teachers' work in the private sector. This research addresses this gap in knowledge and compares the sources of stress experienced by 20 teachers in the state sector to those of 20 teachers in the private sector. The paper is based on qualitative data from a larger study. It analyses data collected in interviews and focus groups with classroom teachers and middle leaders working in mainstream primary and secondary phase education in England. The results emphasise state school teachers' acute distress in relation to workloads driven by accountability cultures. In comparison, private school teachers report less intense experiences of work-related stress, but some identify demanding parents as a concern. The research's novelty lies in this comparison between sectors and these sector specific insights may help to focus school leaders' efforts to improve teaching conditions in both sectors.