This paper starts with theoretical knowledge about sustainable development, notable events related to the concept of sustainability at the global level, and guidelines for including sustainability topics in all areas of life. The paper also emphasizes the foundations of sustainable development, as well as the importance of education for sustainable development. Regarding the potential challenges when implementing the topic of sustainable development in the teaching process, teachers' views on sustainable development from already conducted research are mentioned. The paper analyzes the current position of education for sustainable development in the Republic of Croatia and states the peculiarities of the subject Science, during which it is convenient to include the topics of sustainable development, that is, to realize the educational expectations of the cross-curricular topic Sustainable Development. The second part of the paper is oriented to the results of the conducted research among classroom teachers. The aim was to examine the knowledge of teachers about sustainable development, to determine how they self-assess their own knowledge of the content and areas for the implementation of education for sustainable development, to examine their opinion on the importance of including sustainable development in the teaching of science, and which teaching strategies are most often used in order to realize learning outcomes of the Curriculum of the subject Science and the educational expectations of the cross-curricular topic of Sustainable Development. The results of the research show that teachers are familiar with basic knowledge about sustainable development and consider themselves highly competent to convey certain content from the field of sustainable development. Teachers believe that it is important to develop students' knowledge, skills and attitudes related to sustainable development. Research-based teaching as a teaching strategy is chosen the most by teachers with the aim of realizing subject learning outcomes and cross-curricular educational expectations. Teachers have a positive attitude towards the inclusion of the topic of sustainable development in the teaching of science, they recognize the importance of developing students' competencies, but are at the same time fully aware of the limitations in the educational system and the obstacles to better implementation of the topic of sustainable development in the teaching process.