Southeast Asia is the geographical south-eastern region of Asia, consisting of the regions that are situated south of China, east of the Indian subcontinent, and north-west of mainland Australia which is part of Oceania. Southeast Asia is bordered to the north by East Asia, to the west by South Asia and the Bay of Bengal, to the east by Oceania and the Pacific Ocean, and to the south by Australia and the Indian Ocean. Apart from the British Indian Ocean Territory and two out of 26 atolls of Maldives in South Asia, Maritime Southeast Asia is the only other subregion of Asia that lies partly within the Southern Hemisphere. Mainland Southeast Asia is entirely in the Northern Hemisphere. East Timor and the southern portion of Indonesia are the parts of Southeast Asia that lie south of the Equator.

Asia is the largest continent in the world by both land area and population. It covers an area of more than 44 million square kilometers, about 30% of Earth's total land area and 8% of Earth's total surface area. The continent, which has long been home to the majority of the human population, was the site of many of the first civilizations. Its 4.7 billion people constitute roughly 60% of the world's population.