Controversial issues are a teaching challenge that can either be accepted and pedagogically grasped by the teacher, or repressed. However, there is no generally accepted definition of ‘controversial issues’ in the literature. Most definitions contain behavioural, epistemic and political elements. Hence, controversial issues are topics about which individuals tend to disagree, about which individuals tend to hold conflicting explanations, and about which individuals create solutions based on different values (Cooling, 2012; Hand, 2008; Ljunggren et al., 2015; Stradling, 1984). We collected critical incidents (Flanagan, 1954) from teachers working in the north of Sweden in an Indigenous language zone. We found that the teachers do not consider an given issue as controversial per se, but rather they see controversiality as created in the specific classroom context. For example, one teacher expressed this as follows: “a controversial issue is created through the students in the classroom and what backgrounds they have.” Globalisation and refugee flows have created classrooms with students from the North and South allowing more issues to be perceived as controversial than earlier when school was more homogeneous. In this paper, we problematise the teachers’ construction of critical issue incidents.