The Sihanaka are a Malagasy ethnic group concentrated around Lake Alaotra and the town of Ambatondrazaka in central northeastern Madagascar. Their name means the "people of the swamps" in reference to the marshlands around Lake Alaotra that they inhabit. While rice has long been the principal crop of the region, by the 17th century, the Sihanaka had also become wealthy traders in slaves and other goods, capitalizing on their position on the main trade route between the capital of the neighboring Kingdom of Imerina at Antananarivo and the eastern port of Toamasina. At the turn of the 19th century they came under the control of the Boina Kingdom before submitting to Imerina, which went on to rule over the majority of Madagascar. Today the Sihanaka practice intensive agriculture and rice yields are higher in this region than elsewhere, placing strain on the many unique plant and animal species that depend on the Lake Alaotra ecosystem for survival.

The Malagasy are a group of Austronesian-speaking ethnic groups indigenous to the island country of Madagascar. Traditionally, the population have been divided into ethnic groups. Examples include "Highlander" groups such as the Merina and Betsileo of the central highlands around Antananarivo, Alaotra (Ambatondrazaka) and Fianarantsoa, and the "coastal dwellers" such as the Sakalava, Bara, Vezo, Betsimisaraka, Mahafaly, etc.