amp; Van Hiel, 2011; Czech version Širůček, 2014) consisting of 15 items with 6-point Likert scale measuring 5 sub-scales: desire for predictability, preference of order and structure, discomfort with ambiguity, decisiveness, and close-mindedness. The sample consists of 6 MTs and 6 STs in 6 lower secondary comprehensive classes in 6 schools (ISCED 2A) in the Czech Republic. From each MT/ST we videotaped (teacher and student camera) 6 lessons taught in Civics, Czech or History; conducted an interview, and administered NfCS. STs wrote electronic reflective diaries about their teaching practice. Findings: NfC is related with MTs perception of critical situations in STs’ lessons and with when and how MTs intervene. We describe three types of MTs/STs: with low, middle, high NFC and show MTs interventions during STs’ lessons and STs’/pupils’ responses to them. The findings can be beneficial in MT/ST education in European countries as MTs/STs are exposed to similar conditions. The findings emphasise the role of MT and ST co-operation in ST/MT professional development.