Australasia je agbegbe ni Oseania: Australia, New Zealand, erekusu New Guinea, ati awon erekusu itosi ara won ni Okun Pasifiki. Charles de Brosses ni o koko lo oruko yi ninu Histoire des navigations aux terres australes (1756). O mu wa lati Latin fun "guusu Asia" o si seyato agbegbe yi si Polynesia (ni ilaorun) ati guusuilaorun Pasifiki (Magellanica). Bakanna o tun yato si Micronesia (ni ariwailaorun). Australasia joko lori Abo India-Autralia, pelu India.