The Agreement Governing the Activities of States on the Moon and Other Celestial Bodies, better known as the Moon Treaty or Moon Agreement, is a multilateral treaty that turns jurisdiction of all celestial bodies (including the orbits around such bodies) over to the participant countries. Thus, all activities would conform to international law, including the United Nations Charter.

It has not been ratified by any state that engages in self-launched human spaceflight (i.e., the United States, Russia (or its predecessor the Soviet Union), or the People's Republic of China) since its creation on December 18, 1979, and thus it has little to no relevancy in international law. As of May 2024^[update], 17 states are parties to the treaty.

It was noted that since the 1967 Outer Space Treaty was signed, technologies and society evolved, requiring a redefinition of the rights and responsibilities of citizens and governments alike in the use and development of outer space. The primary stated objective of the 1979 Moon Treaty is "to provide the necessary legal principles for governing the behavior of states, international organizations, and individuals who explore celestial bodies other than Earth, as well as administration of the resources that exploration may yield." It proposed to do so by having the state parties produce an "international regime" that would establish the appropriate procedures (Article 11.5).

The Moon Treaty proposes to establish an "international regime" or "framework of laws" that apply to the Moon and to other celestial bodies within the Solar System, including orbits around or other trajectories to or around them.

The Moon Treaty lays several provisions outlined in 21 articles. In Article 11, the treaty makes a declaration that the Moon should be used for the benefit of all states and all peoples of the international community. It reiterates that lunar resources are "not subject to national appropriation by claim of sovereignty, by means of use or occupation, or by any other means." It also expresses a desire to prevent the Moon from becoming a source of international conflict, so that the resources should be used exclusively for peaceful purposes. To those ends, the treaty lays several provisions, and some of these are paraphrased below:

When compared with the Outer Space Treaty, it reiterates most provisions, and adds two new concepts in order to address the exploitation of natural resources in outer space: to apply the concept of "common heritage of mankind" to outer space activities, and to have the participating countries produce a regime that lays the appropriate procedures for orderly mining. Multiple conferences produced no consensus on these two items.

After the 1967 non-armament Outer Space Treaty was signed, it was followed in 1968 with the United Nations convened UNISPACE, the United Nations Conference on the Exploration and Peaceful Uses of Outer Space. It was the first of a series of UN-sponsored conferences intended to create an international framework of laws to guide humanity's use of outer space resources.

After ten more years of negotiations, the Moon Treaty was created in 1979 as a framework of laws to develop a regime of detailed procedures, and as such, it remained imprecise: its Article 11.5 states that the exploitation of the natural resources of the Moon shall be governed by an international regime that would establish the appropriate procedures. In order to define this regime or laws, a series of UN-sponsored conferences took place, but brought no consensus. The continuing disagreement is based mainly over the meaning of "Common Heritage of Mankind" and on the rights of each country to the natural resources of the Moon.