The security agenda is going global. Key threats such as weapons proliferation, disease, terrorism and climate change cannot be addressed unilaterally by states, and require a global perspective to both understand and respond effectively to them. There are therefore powerful pragmatic reasons for embracing a global security perspective. This article, however, suggests that a compelling moral case also exists for viewing security in global terms. National and international security discourses are at odds with the realities of world politics and orient towards the preservation of a status quo that is failing much of the world s population, now and into the future. In this context, this article makes a case for cosmopolitan ethical principles underpinning a global security perspective. Only an ethics that does not discriminate between groups is defensible as a general set of principles. A global security perspective should be underpinned by three cosmopolitan ethical principles which dictate, firstly, that all security actors have responsibility (albeit differentiated) to create security for all; secondly, they should act with consideration of the future implications of their actions in mind; and, thirdly, they should proceed as if their actions will become global over time and space. While not without challenges and dilemmas, such a perspective is urgently needed in contemporary global politics.