There is a growing interest in teacher quality, which must encompass teacher diversity, including a more age-diverse and ageing teacher workforce. Little is known about how generational change among teachers influences professional dispositions, which are key to teacher quality. This qualitative study investigated how young beginner, mature veteran and older retired teachers in Spain characterise generational groups of teachers according to their professional dispositions. A thematic analysis of data from discussion groups and interviews (n = 24 and n = 60, respectively) showed that the participants (n = 147) identified and had a similar understanding of two core professional dispositions: a sense of vocation and the engagement that it promotes. It was also found that they attributed differences to age, career path, and significant shared experiences. This suggests that, in their perception, these aspects shape their notion of teacher generations, which is important for understanding the contextual and changing nature of professional dispositions.