Introduction This cybersecurity strategy is Estonia’s third national cybersecurity strategy document and defines the long-term vision, objectives, priority action areas, roles and tasks for the domain, being the basis for activity planning and resource allocation. The strategy is based on the lessons learned during the two previous strategy periods (2008-2013 and 2014-2017). As a horizontal strategy, it involves all contributing stakeholders in Estonia: the public sector (both civilian and defence), essential service providers, sectoral entrepreneurs, and academia. The aim of this document is to agree on and create conditions for the implementation of a comprehensive, systematic and inclusive sectoral policy. The 2008 Cyber Security Strategy1 was Estonia’s first national strategy document that recognised the interdisciplinary nature of cybersecurity and the need for coordinated action in the area. It was also one of the first horizontal cybersecurity strategies in the world – it was only after the 2007 cyberattacks against Estonia that cybersecurity began to be perceived as an essential part of national security. The Estonian cybersecurity strategy was among the first of its kind globally. Today, national cybersecurity strategies are commonplace,2 as is the approach that the first Estonian cybersecurity strategy adopted. The 2013 European Union (EU) cybersecurity strategy3 defined a national cybersecurity baseline (designating national competent authorities, establishing national incident response teams, developing a national cybersecurity strategy); the 2016 EU Network and Information Systems Security Directive4 established these as a legal “ Today, cybersecurity is universally accepted as an integral part of the functioning of the state, the economy, internal and external security. 1 https://www.valitsus.ee/sites/default/files/content-editors/arengukavad/kuberjulgeoleku_stratee gia_2008-2013.pdf 2 https://www.itu.int/dms_pub/itu-d/opb/strategy/D-STR-GCI.01-2017-PDF-E.pdf 3 http://eur-lex.europa.eu/legal-content/ET/TXT/PDF/?uri=CELEX:52017JC0450&from=EN 4 http://eur-lex.europa.eu/legal-content/ET/TXT/PDF/?uri=CELEX:32016L1148&from=EN 7