An important dimension of teachers' professional judgments is connected to their educational values and ideals. Teachers' professional judgments are not only informed by instrumental considerations but also affected by what they consider to be educationally worthwhile, that is, what teachers consider to be in their pupils' best interest. This study explores the substance of teachers' educational values and beliefs that underlie their daily classroom interactions. The guiding research question is "How do teachers legitimize their daily classroom interactions in terms of educational values and ideals?" A structured interview procedure was conducted with thirty-seven teachers. With the help of a conceptual framework based on the compound question, "Who should be taught what, how, when and why?", a systematic analysis of the interview data was conducted. This resulted in a typology of six legitimization types that teachers used when interpreting their classroom interactions in terms of their pupils' best interest: (1) a caring legitimization type, (2) a personal legitimization type, (3) a contextual legitimization type, (4) a critical legitimization type, (5) a functional legitimization type, and (6) a psychological legitimization type. A legitimization type entails a systematic description of what teachers consider to be educationally worthwhile. This typology of legitimizations could contribute to the development of an educational vocabulary that enables teachers to inquire, articulate and discuss their educational values and ideals in a deliberate manner.