The name of a people inhabiting the north east of Sri Lanka. They are first mentioned in the Chronicles (Cv.lxxxi.11), in the reign of Vijayabāhu III (1232-36), who, with their help, gained the throne of Sri Lanka.

They appear to have inhabited the frontier country between Jaffna and the Singhalese kingdom and were either subjects of one or other of these states, or affected complete independence, according to the strength of their neighbours.

Vijayabāhu IV made friends with the Vanni chiefs and gave into their hands the protection of Anurādhapura (Cv.lxxxviii.87). They seem to have been a warlike people. Today they occupy a few small villages in the North Central Province of Sri Lanka and go in largely for hunting.

Their origin is unknown, though they are called Sīhalā (e.g., Cv.lxxxiii.10). Several of their chieftains are mentioned by name, as having been overcome by Bhuvanekabāhu I — e.g., Kadalīvāta, Apāna, Tipa, Himiyānaka (Cv.xc.33).

The adjective from Vannī is Vañña. See, e.g., Cv.lxxxiii.10; lxxxvii.26.