Defence agencies across the globe identify artificial intelligence (AI) as a key technology to maintain an edge over adversaries. As a result, efforts to develop or acquire AI capabilities for defence are growing on a global scale. Unfortunately, they remain unmatched by efforts to define ethical frameworks to guide the use of AI in the defence domain. This chapter provides one such framework. It identifies five principles – justified and overridable uses; just and transparent systems and processes; human moral responsibility; meaningful human control; reliable AI systems – and related recommendations to foster ethically sound uses of AI for national defence purposes.