The theoretical part of the thesis analyzes the basic characteristics of the concept of sustainable development by the means of a historical overview of the most significant theoretical theses, approaches to the concept as a developmental, temporal, multidimensional, and general social and global concept, overview of certain models and dimensions and their development, and implications for the educational system. As for the context of development of education for sustainable development in primary schools, the overview of key changes, characteristics and holistic approaches is given in the separated chapters. In this regard, components of sustainable schools and eco-schools are presented and analyzed as the most important models of a holistic approach in schools. The last theoretical chapter provides a global, international and national overview of development and implementation of education for sustainable development within educational systems, particularly schools, as well as overview of programmes, eco-school projects and current research trends. Besides the research methodology, the empirical part of the thesis provides the results of the research on the implementation of the concept of education for sustainable development in the official records related to primary education in the Republic of Croatia and implementation of contents of education for sustainable development concept in primary schools. It also includes the investigation of attitudes and opinions held by primary school teachers, identification of school status with regard to the completion of an international eco-school programme, and assessment of disadvantages and/or obstacles related to the implementation of contents of education for sustainable development concept in primary schools. Furthermore, the results obtained by investigating the levels of primary school teacher professional training in the field of education for sustainable development are also given including the assessment of single forms of professional training, level of qualification for educational work in the field of implementation of education for sustainable development concept, level of attained competences in education for sustainable development, and level of attained knowledge about education for sustainable development concept with regard to the county, activity in schools, qualification, work experience, and school status. The research was also oriented towards the identification of levels related to the development and implementation of sustainability dimensions in primary schools as well as aspects of teacher's work that contribute to a more significant implementation of education for sustainable development concept in school work. By investigating primary school teacher attitudes and opinions, we got an insight into important aspects of future school work with regard to education for sustainable development. Besides the given conclusions, we have also pointed to certain guidelines aimed at the improvement of single aspects of school work in the field of education for sustainable development. The descriptive method was applied in the thesis as well as statistical procedures to calculate multivariate statistics (factor analysis, one-way analysis of variance, Kruskal-Wallis test, Mann-Whitney U test, t-test and multi-regression analyses). The research resulted in important cognitions about the state and future of development of education for sustainable development in schools and pointed to disadvantages and/or obstacles, as well as possibilities for the development and implementation of education for sustainable development concept, significance of eco-school status, and aspects of teacher's and school work necessary for the development and improvement of a holistic approach within the implementation of the concept of education for sustainable development in schools and more sustainable schools of the future.