In the spring of 2010, ninth graders (N = 401) of various lower secondary schools in Southern Bohemia fi lled in a questionnaire on unethical behaviour in schools. Based on the students’ self-reports on how often they had participated in behaviour that can be interpreted as cheating, two types of cheating were induced via exploratory factor analysis: cheating and deceiving. The questionnaires included two open-ended questions which were answered by 256 students. This paper analyses the students’ answers from the perspective of their approaches to particular instances of unethical behaviour. At the same time, the paper also puts them into the context of the afore-mentioned factors. The analysis of students’ answers has confi rmed that students tolerate more such a type of behaviour that is possible to describe as cheating and which mostly takes the form of students copying answers from other students. Two new fi ndings arise from students’ open-ended answers: fi rst, students strongly dislike teachers’ behaviour which they interpret as unfair to them (e.g. a teacher is favouring a given student or giving unannounced tests etc.) Second, the analysis has confi rmed a high degree of students’ tolerance towards cheating via the Internet.