Many South African schools are underperforming academically and are labelled as trapped or yo-yo schools. The motivation and commitment of school leadership and educators play a critical role in realising improved academic results and sustainable improvement. In the study reported on here a 2-fold perspective was used to explore the problem of motivation: (a) motivational factors influencing sustainable improvement in performing, trapped and yo-yo schools and (b) how the self-determination theory (SDT) can cast light on the issue of motivation and sustainable improvement in schools. Following a qualitative, exploratory, descriptive design, purposive sampling was used to select 6 secondary schools. We conducted individual and focus group interviews with the 6 school principals and 36 educators and heads of department who participated in the study. The findings reveal external factors that operate as negative and positive influences on the participants’ controlled motivation, amotivation and autonomous motivation. Reactions to the labelling of the schools and the motivation brought about by the school leadership styles enabled the participants to internalise the goals of the interventions of the Department of Basic Education for school improvement. One-size-fits-all interventions for school improvement are not effective in all trapped schools. Interventions should be based on individual analyses of root causes of problems and not on the symptoms.