Activity in Outer Space has increased significantly in recent times, with new Space actors and new technologies emerging. This has resulted in Outer Space becoming a crowded and tense environment in which the possibility of the use of weapons grows ever nearer. The consequences of such weapons use in Outer Space would be felt by humankind as a whole. The law that governs the conduct of armed conflicts, and the use of weapons during these periods of conflict, is International Humanitarian Law (IHL). However, weapons regulation in IHL struggles to keep pace with the development of weapons technologies which can be used in Outer Space. In addition, International Space Law (ISL) does not prohibit the use of all weapons in Outer Space. This research addresses this gap in the ISL and IHL frameworks with regards to the regulation of weapons use in Outer Space. IHL was founded on the basis of four principles – distinction, military necessity and proportionality, all of which stem from the central principle of humanity. It was in the Martens Clause of the 1899 Hague Convention II that this central principle of humanity was referenced as providing guidance and applying in the absence of express legislation. Therefore, the principle of humanity is currently addressing this gap by providing a minimum standard of protection based on the considerations of what is in the interests of humanity with regards to the regulation of the use of weapons in Outer Space. This research forms recommendations for express regulation, from the perspective of this central principle of humanity, as it is premised that this approach will inform regulation with a view to protecting humankind from the consequences of the use of weapons in Outer Space.