In classroom interaction, participants are not only oriented to interactional principles for mundane talk, but also to pedagogical principles. In this paper, the interplay between these principles is revealed by means of a conversation analytic study into student-initiated student-teacher interactions during desk work in Dutch secondary schools. It is investigated from a participants’ perspective how teachers depart from the mundane interactional constraints imposed by students’ requests for assistance. The analysis shows that there are several ways teachers depart from these constraints and that teacher and students do not necessarily show an orientation to this departure as being problematic. Rather, the departure can be related to considerations concerning the pedagogical nature of these interactions. By studying the interactional departures from mundane principles, more insight is provided in the organization of classroom interactions that are started by students’ requests for assistance.