The Semang are a Negrito ethnic group of the Malay Peninsula. Lowland Semang tribes are also known as Sakai, although this term is considered to be derogatory by the Semang people. They are probably the indigenous peoples of this area. They have been recorded to have lived here since before the 200s Common Era (CE). They are ethnologically described as nomadic hunter-gatherers.

They are thought to be related to other Negritos, such as the natives of the Andaman Islands and the Aetas of the Philippines. Their languages, however, are Aslian, in the Mon-Khmer family.

The Semangs live in caves or leaf-shelters that form between branches. A waistcloth for the men, made of tree bark hammered out with a wooden mallet from the bark of the terap, a species of wild bread-fruit tree, and a short petticoat of the same for the women, is the only dress worn; many go naked.

Tattooing, or rather scarring, is practised. They draw the finely serrated edge of a sugarcane leaf across the skin and rub in charcoal powder.