Sumbawa is an Indonesian island, located in the middle of the Lesser Sunda Islands chain with Lombok to the west and Flores to the east. Sumba is further offshore to the southeast. It is in the province of West Nusa Tenggara.

Sumbawa is three times the size of Lombok with a population of around one million. It marks the end of Indian influence and the beginning of what are sometimes referred to as the "pagan" eastern islands. Four principalities in western Sumbawa were dependencies of the Majapahit kingdom of eastern Java. Because of Sumbawa's natural resources it was regularly invaded by outside forces - Javanese, Dutch, Makassarese. The Dutch first arrived in 1605, but did not effectively rule Sumbawa until the early 20th century. The Balinese kingdom of Gelgel ruled western Sumbawa for a short period as well.

Islam was introduced via the Makassarese of Sulawesi. Sumbawa has historically had two major linguistic groups who spoke languages that were unintelligible to each other. One group centered in the western side of the island speaks Sumbawanese which is similar to the Sasak language from Lombok; the second group in the east speaks Bima . The kingdoms located in Sumbawa Besar and Bima were the two focal points of Sumbawa.

This division of the island into two parts remains today; Sumbawa Besar and Bima are the two largest towns on the island, and are the centers of distinct cultural groups that share the island.

Sumbawa lies within the Pacific Ring of Fire. It is a volcanic island, including Mount Tambora which exploded in 1815, the most destructive volcanic eruption in modern history, larger even than Krakatoa, between Java and Sumatra. The Tambora eruption killed nearly 100,000 people outright, and many more indirectly. The vast quantities of ash it launched into the upper atmosphere caused the "year without a summer."

See also: Islands of Indonesia