One of the priorities of the European Commission is the development and integration of open science policy, which will “improve the quality, efficiency, and responsiveness of research” (European Commission, 2021). The EU funded project FOSTER Plus (Fostering the practical implementation of Open Science in Horizon 2020 and beyond) defines open science as “practice of science in such a way that others can collaborate and contribute, where research data, lab notes, and other research processes are freely available, under terms that enable reuse, redistribution and reproduction of the research and its underlying data and methods” (FOSTER, 2017). Over the years, several institutions and initiatives in Croatia have advocated openness and built support for open science. In June 2021, SRCE – University of Zagreb University Computing Centre led the launch of the National Open Science Cloud (NOSC) Initiative named the Croatian Open Science Cloud (abbrev. locally HR-OOZ) Initiative. The Initiative gathered prominent national institutions with an active role in the field of open science and it includes representatives of all important stakeholder groups: research performing organizations (RPO), research funding organizations, research supporting organizations and policy makers. List of RPOs that joined the Initiative includes all public universities and Croatian representatives or national coordinators of European Research Infrastructure Consortium (ERICs): Institute of Ethnology and Folklore Research (DARIAH), Faculty of Humanities and Social Sciences of the University of Zagreb (CLARIN and CESSDA), Ruđer Bošković Institute (CERIC, OpenAIRE NOAD, NI4OS-Europe project partner). The main research funding organization – Croatian Science Foundation also joined the initiative together with the main policy maker – Ministry of Science and Education of the Republic of Croatia. Besides SRCE, which is the main e-infrastructure and data services provider for the Croatian higher education and research system, the national Research Data Alliance node and the NI4OS-Europe project partner, the National and University Library in Zagreb joined the Initiative. Inclusion of many institutions and representatives of all stakeholder groups will hopefully ensure greater acceptance, impact and sustainability of the Initiative’s results. Active involvement of relevant stakeholders in creating required preconditions for the implementation, realization, and promotion of open science should lead to improved research conditions which is necessary to achieve top research results for the benefit of the academic community as well as the entire society of the Republic of Croatia. The Initiative aims to build a modern, high-quality, internationally relevant, and competitive science system based on the principles of open science, which is harmonized and connected with European Research Area and relevant European initiatives. The Initiative has two main goals. The first goal is to setup the HR-OOZ which includes tasks of defining its organizational and governance structure, defining the technological principles of the components that will make the HR-OOZ.