Antarctica is not officially owned by any government. It is not a country. However, there are over 12 countries that claim rights to certain portions of the continent.
These countries include the United States, United Kingdom, Argentina, Chile, New Zealand, Japan, France, South Africa, Norway, Belgium, Australia, and Germany. These countries signed the Antarctic Treaty in 1959.
Of all these countries, the United Kingdom is the first to lay claim of some portion of Antarctica in the 19th century. Antarctica is free of military activities, mining, and the use of nuclear explosions. Antarctica remains a nature reserve and strictly for scientific research purposes.
In summary, nobody owns Antarctica. Antarctica does not have a government of its own. Several countries have territorial claims on the continent.