The Malay Archipelago is the archipelago between Mainland Southeast Asia and Australia, and is also called Insulindia or the Indo-Australian Archipelago. The name was taken from the 19th-century European concept of a Malay race, later based on the distribution of Austronesian languages. It has also been called the "Malay world", "Nusantara", and the "East Indies" over time. The name is controversial in Indonesia due to its ethnic connotations and colonial undertones, which can overshadow the country's diverse cultures.

Situated between the Indian and Pacific oceans, the archipelago of over 25,000 islands and islets is the largest archipelago by area and fifth by number of islands in the world. It includes Brunei, East Timor, Indonesia, Malaysia (specifically East Malaysia), Papua New Guinea, the Philippines, and Singapore. The term is largely synonymous with Maritime Southeast Asia.

The term "Malay Archipelago" was derived from the European concept of a "Malay race" (a culturally-similar non-Oceanian subset of the Austronesian peoples),^{[dubious – discuss]} an outdated racial concept proposed by European explorers.

The 19th-century naturalist Alfred Wallace used the term "Malay Archipelago" as the title of his influential book documenting his studies in the region. Wallace also referred to the area as the "Indian Archipelago" and the "Indo-Australian Archipelago". He included the Solomon Islands and Malay Peninsula in the region due to physiographic similarities. As Wallace noted, there are arguments for excluding Papua New Guinea for cultural and geographical reasons: Papua New Guinea is culturally quite different from the other countries in the region, and it is geologically not part of the continent of Asia, as the islands of the Sunda Shelf are (see Australia).

Insulindia is a somewhat archaic geographical term for Maritime Southeast Asia, sometimes extending as far as Australasia. More common in Portuguese and Spanish, it is also sometimes used in art history or anthropology to describe the interface zone between the cultures of Oceania and Southeast Asia.

Insulindia is used as a geopolitical term in academic discussions of the former European colonial possessions within Maritime Southeast Asia, especially Dutch East Indies and Portuguese East Indies ("Portuguese Insulindia") much as former French colonial possessions in Southeast Asia are still termed French Indochina. It is also used to describe and locate the Chinese cultural diaspora (the "insulindian Chinese") across the islands of Southeast Asia.

The archipelago was called the "East Indies" from the late 16th century and throughout the European colonial era. It is still sometimes referred to as such, but broader usages of the "East Indies" term had included Indochina and the Indian subcontinent.

The term "Maritime Southeast Asia" is largely synonymous, covering both the islands in Southeast Asia and nearby island-like communities, such as those found on the Malay Peninsula.