In the article three Icelandic research projects are examined, two doctoral theses and one master’s thesis, with a view to mapping the knowledge that those projects have created while also considering what knowledge is lacking in the field of research in religious education in Iceland. The selected projects are chosen on the basis of their focus on religious education at schools, and they are examined from the perspective of what knowledge they have provided and what conclusions can be drown from their results about the status and role of religious education in compulsory schools in Iceland. Research in the field of religious education in Iceland has been rather limited, and the question arises, what knowledge is available in that area in the country? All three projects reflect the development of Icelandic society from being relatively homogeneous in religious matters to growing secularization and increasing religious diversity and pluralism. Although their objectives are different, they clearly show how the development of the society affects emphases in the school’s religious education. Therefore their results and discussion provide a foundation of knowledge on religious education in compulsory schools in Iceland or other multicultural societies. In the first projects the historical development in Iceland is described and compared with the development in the other Nordic countries (Denmark, Norway and Sweden) and it effectively creates the background for the other projects. The development of Christian and religious education in Iceland is shaped by the development of the society. In the two other research projects the conclusion is that religious education must take into account the increasing diversity and put the students and their diverse experiences in focus. The emphasis is placed on the idea that the approach to religious education needs to be multicultural, precisely because there are students in the schools with different cultural and religious backgrounds and experiences. It is necessary to take this into account, since factors such as family, home and school affect each other.