This National Plan Open Science sets out what the Dutch parties involved in creating this Plan are already doing and what they plan to do to grasp the opportunities and at the same time make science even more accessible to others. A major boost is required if these initiatives are to be coordinated and the great ambition realised. That is why this Plan lists the ambitions and provides details of the parties intending to take action, as well as the timeframes within which they believe they can realise their objectives. The key ambitions are: (1) Full open access to publications in 2020: Continue the Dutch approach for all Dutch research organisations and research areas whilst recognising their differences and similarities; (2) To make research data optimally suited for reuse: To set clear and agreed technical and policy-related preconditions to facilitate reuse of research data, including provision of the necessary expertise and support; (3) Recognition and rewards: To examine together how open science can be an element of the evaluation and reward system for researchers, research groups and research proposals; and (4) To promote and support: To establish a ‘clearing house’ for all information regarding all available research support. With the ambitions set out in this plan the Netherlands is responding to the Amsterdam Call for Action on Open Science published in 2016, the conclusions of the Competitiveness Council in May 2016, and to the in the letter to Parliament concerning open science confirmed question by the State Secretary for Education, Culture and Science (January 2017). Open access to publications and optimal reuse of research data are becoming the standard for all knowledge institutes and research areas. The motto here is as open as possible, as closed as necessary. - These reports are available under a CC-BY 4.0 license (https://creativecommons.org/licenses/by/4.0/).