The EU and NATO are targeted by the very same cyber-attack vectors that undermine all levels of society, threatening civil, political, economic, and military security. Much of cyber threats go undetected, unacknowledged, or inadequately addressed by decision-makers. Stakeholders in various sectors are becoming more informed and engaged around cybersecurity and cyber defence issues, but the challenges remain daunting. In this context, the Estonian Presidency of the Council of the EU convened a flagship conference to stimulate new thinking on EU-NATO cybersecurity and defence cooperation in November 2017. The brief summarizes the discussions and offers recommendations to address the most pressing issues on the EU-NATO cyber agenda.