This article analyzes the ways in which emotions are constituted and mobilized by teachers to respond to growing diversity and multiculturalism in schools. The analysis is based on a two-year ethnographic study conducted in three Greek-Cypriot primary schools that are "multicultural". The following focus questions are addressed: (1) How do teachers' emotional experiences of growing diversity and multiculturalism in schools form particular economies of effect?; and (2) What is the nature of these economies of affect and in what ways is it possible to form an ethic of discomfort as a space for constructive transformations in multicultural schools? An ethic of discomfort is theorised as an economy of affect that uses discomfort as a point of departure for individual and social transformation. The outcomes of this study show that teachers experience intense emotional ambivalence in their efforts to cope with growing diversity and multiculturalism in schools. It is argued, however, that the capabilities of teachers to cope with growing diversity and multiculturalism are enhanced, if an ethic of discomfort is constituted in multicultural schools. The implications of this study are discussed in relation to teaching and teacher education and suggest that constituting an ethic of discomfort offers opportunities to challenge structures of power, privilege, racism, and oppression. (Contains 2 notes.)