Nobody — on purpose. In 1967, at the height of the space race, the world agreed that no flag on the Moon would ever mean ownership. That treaty still governs everything above your head, and it's being stress-tested right now.
The treaty that beat Apollo to the Moon
Two years before Neil Armstrong planted a flag, the United States and the Soviet Union — rivals in everything — signed the Outer Space Treaty of 1967, and more than 110 nations have joined since. Its core rules are short enough to memorize: space is 'the province of all mankind'; no nation may claim sovereignty over the Moon or any celestial body; no weapons of mass destruction in orbit; astronauts are 'envoys of mankind' whom every nation must help; and each state is responsible for what its citizens and companies do up there. That last clause matters more every year: legally, a private rocket flies under its country's flag and its country's responsibility.
So the flag was just a flag
Apollo's flag was symbolism, not a land claim — the US said so at the time. The follow-up treaty that tried to go further, the 1979 Moon Agreement, declared lunar resources humanity's 'common heritage' and flopped: only about 18 nations ever joined, none of them major space powers. And no, the novelty 'lunar deeds' sold online carry no legal force anywhere. The honest state of the law: no one can own the Moon's land — but the treaty was written before anyone could use it, and using is where the argument now lives.
Water ice makes it real
The question stopped being philosophical when probes confirmed water ice in the Moon's polar craters — drinkable, breathable, splittable into rocket fuel, and exactly where every agency wants to build. Can you own what you extract, even if you can't own the ground? The United States answered yes for its companies in a 2015 law, Luxembourg and others followed, and the Artemis Accords — a set of principles now signed by more than 50 nations — say resource extraction is compatible with the treaty, alongside rules like public registration and 'safety zones' around operations. Notably absent from the signatures: Russia and China, who are building their own lunar plans. The Moon's law is being written the way sea law once was: by whoever shows up, in the order they arrive.