This special issue gathers together a selection of papers presented by international experts during a workshop entitled ‘Ethics of Cyber-Conflicts’, which was devoted to fostering interdisciplinary debate on the ethical and legal problems and the regulatory gap concerning cyber conflicts. The workshop was held in 2013 at the Centro Alti Studi Difesa in Rome under the auspices of the NATO Cooperative Cyber Defence Centre of Excellence (NATO CCD COE). This NATO-accredited international military organisation that has always placed a high value on an interdisciplinary approach to cyber defence, uniting as it does perspectives from technical, policy, legal, and strategic domains. The Centre’s mission is to enhance capability, cooperation, and information-sharing between NATO, its member states, and partner countries in the area of cyber defence by virtue of research, education, and consultation. The workshop was one of the projects supported by the Centre to achieve this mission.