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 geopolitically, it covers about 12,000,000 km (4,600,000 sq mi), or about 28 percent of the Asian continent, about 15 percent bigger than the area of Europe, though some categorize Tibet, Xinjiang, and Mongolia as Central Asia. In some contexts, Vietnam is considered part of East Asia because of the significant Chinese cultural influence it has experienced.

More than 1.5 billion people, about 38 percent of the population of Asia or 22 percent of all the people in the world, live in geographic East Asia, which is about twice the population of Europe. The region is one of the world's most populated places, with a population density of 131 inhabitants per square kilometre (340 /sq mi), being about three times the world average of 45 /km (120 /sq mi). Using the UN subregion definitions, it ranks second in population only to South 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.

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 more recently Christianity in South Korea. East Asian calendars are often derived from Chinese Calendar. This combination of language, political philosophy, and religion (as well as art, architecture, holidays and festivals, etc.) overlaps with the geographical designation of East Asia for the most part, with a few exceptions, such as the overseas Chinese (including those in Singapore, Malaysia, Philippines, Vietnam, and the West).