In Poland, a country with a very high level of religiosity, religious education at school is confessional but not compulsory: it is an optional subject chosen by the student. In this article, we explore attitudes regarding participation in religion classes and explanations of the purpose of religious education as provided by adolescent students. We refer to the findings of our research on the rationality of school education and apply them to research on religious education. Rationality is defined as the logic of justifying the purpose of school education and four rationalities: praxeological, emancipatory, hermeneutic, and negational are distinguished. In a large and representative sample of secondary school students (N = 2,810), we examined the relationship between types of rationality and students' attitudes and opinions towards religious education in school. We observed that high school students perceived religious education as highly conservative and declared the strongest support for more dialogical and liberal religious education. Moreover, students' hermeneutical rationality was the primary factor associated with their lack of satisfaction with the current religious education and postulates to change it into a more dialogical one.