European societies are becoming increasingly multicultural and religiously pluralistic. Learning to live with social, cultural, ethnic, gender, religious, and other diversities is one of the greatest challenges of contemporary education. The necessity of coexistence with those who are different calls upon all of us, especially schools, to a new level of thinking and action. Classrooms in many schools are not only multicultural but also multireligious, making it crucial for democratic societies to address interreligious issues through education. The natural place within the school system for learning about other faiths, religions, worldviews, and cultures and for fostering religious dialogue is religious education. Therefore, religious education must not only satisfy the teaching of theology of the parent religion but also incorporate goals contributing to intercultural upbringing and education into its curriculum. As the primary carrier of religious education in the Croatian educational system, even Catholic Religious Education cannot be exempt from the changes brought by multicultural society. Therefore, it is necessary for it to incorporate elements of intercultural education into its curriculum. To establish how secondary Catholic Religious Education in Croatia attempts to respond to these challenges, the aim of this doctoral thesis was to examine the presence of the religious dimension of intercultural education in the part of the Curriculum for Catholic Religious Education for primary and secondary schools in Croatia, focusing on secondary education. The work consists of theoretical and research parts. The first chapter of the theoretical part explains the importance of interculturalism for the educational process, the specifics of its religious dimension, and presents the legal and pedagogical assumptions that enable and encourage the introduction of this type of interculturalism into the educational systems of European countries and the educational system of the Republic of Croatia. Contemporary European societies are characterized by increasing cultural, ethnic, religious, ideological, political, and economic diversity. Learning to live together in such a diverse world becomes one of the greatest challenges of contemporary education. In response to this situation, educational authorities in many European countries have begun to place increasing emphasis on intercultural education. Sensitivity to the religious dimension of this type of education comes to the fore especially after September 11, 2001. It was then realized that religions have the potential to incite believers to violence, but they also have the potential to promote values of respect, justice, and compassion. Such a situation prompted European governments to take religion seriously at the political and legislative levels and to intensify discussions on the role of religious and non-religious worldviews in shaping society, especially the role of religion in the educational system. Many European documents, symposia, publications, and research have confirmed the importance of studying religion in the educational system and educating students for interreligious dialogue. Recommendations emphasizing the importance of equipping students for life in a multicultural world, including its religious dimension, can also be found in Croatian educational documents and pedagogical literature. The second chapter of the theoretical part provides an overview of Catholic church documents dealing with ecumenical and interreligious dialogue, containing sections highlighting the need for learning about different Christian communities, religions, new religious movements, and worldviews. Religious pedagogy calls this type of learning ecumenical and interreligious learning, and the definition of these terms is based on a correct understanding of the concepts of ecumenism and interreligious dialogue. These concepts have become integral parts of Catholic Religious Education thanks to the influence of church documents from the Second Vatican Council onwards. Church documents primarily call for knowing one's own religious tradition. Such knowledge can help believers maintain their identity without crisis when encountering members of other faiths and worldviews. In addition to understanding your own religious tradition, church documents also stimulate meeting other Christian churches and communities. This requirement arises from an increasing ecumenical awareness that requires mutual understanding of different Christian denominations with the aim of reestablishing unity. Church documents also stimulate meeting members of other religions and worldviews. This knowledge helps believers overcome prejudices they may have about others and facilitates finding common ground around which they can build coexistence. The third chapter of the theoretical part provides an overview of the presence of the religious aspect of interculturality in six European Religious Education curricula, the explanation of the different aspects of school religious education in the Croatian educational system, and overview of the development of the religious aspect of interculturality within Catholic Religious Education in Croatia from its introduction to the contemporary curriculum. Although there is no single European model of religious education and intercultural education, curricula for Catholic religious education in different countries clearly show that, regardless of the cultural context and the level of religious pluralism, educational and church authorities responsible for the Catholic Religious Education curriculum take seriously the need for ecumenical, interreligious, and intercultural education. Even Catholic religious education, as the most prevalent form of religious education in the Croatian educational system, takes into account the need for integrating intercultural content into its own curriculum. All three principles on which its presence in the educational system of the Republic of Croatia is based allow for the presence of the religious dimension of interculturality in the religious education curriculum. Since the introduction of Catholic religious education into the Croatian educational system in the school year 1991/1992, all primary and secondary school plans and programs have shown openness to the religious dimension of interculturality in their basic principles. Even the latest religious education curriculum follows the tradition of previous religious education plans and programs, but in a somewhat expanded form. The research part presents the results of the research that established the extent to which the new Curriculum for Catholic Religious Education for primary and secondary schools in Croatia, in the part concerning secondary education, contains educational outcomes that deal with content related to various Christian denominations, religion, major world religions, sects and new religious movements, atheism, agnosticism, ecumenism, and interreligious dialogue, which domains of Bloom's taxonomy the verbs used in the educational outcomes related to the religious dimension of interculturality belong to, and how the contents related to ecumenical learning relate to the contents related to interreligious learning. The part of the new Eeligious Education curriculum concerning secondary education contains 14.09% of outcomes that can be classified into the category of the religious dimension of intercultural education. Of these religious intercultural outcomes, 19.51% belong to ecumenical learning, and 80.49% to interreligious learning. Although outcomes containing the religious dimension of interculturality are present in all grades and domains, they are most prevalent in the first year of secondary school and in domains A and D. Regarding the structure of the content of the religious dimension of interculturality, Orthodox and Protestant Christianity is represented with 12.19%, ecumenism with 7.32%, religion (in general) with 9.76%, major world religions with 29.27%, sects and new religious movements with 2.44%, non-religious worldviews with 17.07%, and interreligious and intercultural dialogue with 21.95%. The verbs used in the educational outcomes containing the religious dimension of interculturality belong to the cognitive domain of Bloom's taxonomy in 91.3% of cases, and to the affective domain in 8.7% of cases. In the cognitive domain, the most prevalent verb is "explain", while in the affective domain, it is "recognize."