This study analyzes situations where teachers' loyalties to colleagues are in conflict with their loyalty to their students. According to written reports about ethical conflicts from 163 teachers in different, compulsory schools, teachers would have liked to report bad treatment of students by teachers or bad institutional policies towards students, but they did not break their loyalty to their colleagues and institutions. Ethical conflicts were found to arise from teachers' awareness of both eye-witness and hearsay problem situations between teacher and student and between student and institution. The teachers delivered 256 examples of experienced ethical conflicts, most involved caring for the student and questioning of a colleague's behavior towards students. The ethical metaphor of "whistleblowing" is used to analyze the universal difficulty of confronting a colleague. To blow the whistle on another teacher involves interfering in a colleague's private space--something no teacher wants to experience personally. In conclusion it would seem that teachers can be morally good only when the act does not conflict with an institutional norm and when it does not interfere with a colleague's privacy; also that it would be hardly possible to make ethical norms explicit in order to strengthen professional ethics in the teaching profession. (Contains 23 references.) (NAV)