This thesis presents an analysis of the content related to sustainable development inside primary school and high school curriculum in Croatia and analysis of the curricular theme Sustainable Development in the official National Curriculum Framework. The analysis is based on the main components of the currently used primary and high school curriculum, as well as curricular theme Sustainable Development in the official National Curriculum Framework which will be experimentally applied as part of the curricular reform, in the first, fifth and seventh grade of elementary school and first grade of gymnasium, starting from the school year 2019/2020. Partial comparison of the similar components within the mentioned documents was done and the key content was synthesized by tables. Significant differences are found in the structure and content of the documents, as well as in the position of this topic. Educational goals and tasks in the current curriculum are not clearly related to the content, nor are they synchronized between subjects and educational cycles. Curricular theme Sustainable Development contains precisely elaborated educational expectations and direct recommendations for their implementation. The views and experiences of the geography teachers, related to sustainable development, were examined in order to gain a deeper insight into the position of this curricular theme in the educational system in Croatia.