Justification is required in reading in French class in Quebec’ high schools, in particular to justify interpretation, reaction or appreciation of a text. However, little is known about the uses that teachers make of justification in the context of their teaching of reading. Exploratory research conducted with 12 French teachers has revealed needs to clarify what constitutes justification in French class to equip teachers to make more diversified use of it that is better aligned with students’ learning needs.