This paper examines whether the relationship between transformational leadership and organisational citizenship behaviours is contingent on public service motivation (PSM). We propose that PSM may reduce followers’ reliance on the motivational behaviours of transformational leaders in public sector organisations. Using a sample of Mexican employees we tested this proposition with structural equation modelling. Our results show that public sector followers higher in PSM placed less reliance, than those lower in PSM, on transformational behaviours. A follow-up study in private sector organisations did not reveal a similar interaction effect. These findings appear consistent with previous research demonstrating that PSM is more aligned to the goals and values of public rather than private sector organisations