East Asia or Eastern Asia (the latter form preferred by the United Nations) is a subregion of Asia that can be defined in either geographical or cultural terms. Geographically and geo-politically, it covers about 12,000,000 km² (4,600,000 sq mi), or about 28 percent of the Asian continent, about 15 percent bigger than the area of Europe.

More than 1.5 billion people, about 38% of the population of Asia or 22% of all the people in the world, live in geographic East Asia, about twice Europe's population. The region is one of the world's most populated places, with a population density of 133 inhabitants per square kilometre (340 /sq mi), being about three times the world average of 45 /km² (120 /sq mi), although Mongolia has the lowest population density of a sovereign state. Using the UN subregion definitions, it ranks second in population only to Southern Asia.

Historically, many societies in East Asia have been part of the Chinese cultural sphere, and East Asian vocabulary and scripts are often derived from Classical Chinese and Chinese script. Sometimes Northeast Asia is used to denote Japan and Korea. Major religions include Buddhism (mostly Mahayana), Confucianism or Neo-Confucianism, Taoism, Chinese folk religion in China, Shinto in Japan, Shamanism in Korea, Mongolia and other indigenous populations of northern East Asia, and recently Christianity in South Korea. The Chinese Calendar is the root from which many other East Asian calendars are derived.