The motivation to teach is a powerful, yet neglected, force in teaching at institutes of higher education. A better understanding of academics' motivations for teaching is necessary. The aim of this mixed-method study was to identify groups with distinctively different motivations for teaching. Six clusters were identified: expertise, duty, subject, passion, reluctance and incompetence. The teachers in these groups differed in perceived personal effectiveness, interest and effort towards teaching. Interview data revealed the competitive function of research and the importance of the subject matter taught. The clusters containing teachers who prioritise the teaching process over the teaching content were the ones with the highest overall motivation scores.