Teachers encounter immense variety in literary competence among students in their secondary school classrooms. Yet, little is known about how they perceive and deal with this variety. Moreover, little is known about the literary development that students undergo during their school career and the different levels of development that can be identified. The aim of the present study is to design an instrument that can help to describe relevant differences in literary competence between students and to specify the individual literary development process of students in upper secondary education (aged 15-18). To tie in with teaching practice, we designed a research method by which we could explore the shared pedagogical content knowledge of a diverse group of six expert teachers. With the aid of questionnaires and panel discussions, data was collected on the following question: what does a student with a particular level of literary competence demonstrate with a particular literary text? The data analysis resulted in 14 indicators of literary competence which we then used to describe six successive competence levels. These levels are validated by both developmental theory and the practice of literature teaching. The following is appended: "Data matrix: Teachers' pedagogical content knowledge about levels of literary competence in upper secondary education."