The development of technology to enhance the exploration and use of outer space has continued at a rapid rate ever since the space age began in 1957. Most military leaders regard space-related technology as an integral element of their strategic battle platform and state security. This reflects the changing technological nature of armed conflict, which challenges many aspects of international law, including the regulation of warfare. The continuing development of commercial and military space technology challenges the core principle of the ‘peaceful purposes’ doctrine that underpins the international regulation of outer space. This chapter explores the development of activities in outer space, the regulation of space security and the application of the United Nations (UN) space treaties. With a focus on the laws of war to the use of outer space during armed conflict, it looks at their practical application in the Asia-Pacific region, and offers some reflections as to what is required to properly address the issue.