The barasingha (Rucervus duvaucelii syn. Cervus duvaucelii), also called swamp deer is a deer species currently found in isolated localities in northern and central India, and southwestern Nepal. It is extinct in Pakistan and Bangladesh.

The specific name commemorates the French naturalist Alfred Duvaucel.

The most striking feature of a barasingha is its antlers, with 10 to 14 tines on a mature stag, though some have been known to have up to 20. The name is derived from this characteristic and means “12-tined or horned” in Hindi.  In Assamese, barasingha is called dolhorina; dol meaning swamp. In central India, it is called goinjak (stags) or gaoni (hinds).

The Barasingha is a fairly large deer species that may stand 47 to 53 in at the shoulder and 71 inches in head-and-body length. Stags (male deer) are notably heavier, at 370 to 620 lb, than does (female deer), at 290 to 320 lb. Average antlers may measure 30 in round the curve with a girth of 5.1 in at mid beam.A record antler measured 41.0 in round the curve.

In central India, the herds comprise on average about 8–20 individuals, with large herds of up to 60. There are twice as many females than males. During the rut they form large herds of adults. The breeding season lasts from September to April, and births occur after a gestation of 240–250 days in August to November. The peak is in September and October in Kanha National Park.They give birth to single calves.

They are basically crepuscular. They are less nocturnal than the sambar deer. When alarmed, they give out shrill, baying alarm calls.

Captive specimens live up to 23 years.