The Sri Lankan junglefowl (Gallus lafayettii, also spelled Gallus lafayetii) is the national bird of Sri Lanka and a member of the Galliformes bird order also known as the Ceylon junglefowl or Lafayette's junglefowl. It is related to the red junglefowl (Gallus gallus), the wild junglefowl from which the chicken evolved. A whole-genome molecular study, however, reveals that the Sri Lankan and grey junglefowls are genetically related to the red junglefowl. Sri Lankan junglefowl and red junglefowl split about 2.8 million years ago, while Sri Lankan junglefowl and grey junglefowl split about 1.8 million years ago.

There is also evidence of introgressive hybridization from Sri Lanka junglefowl in domestic chicken. The scientific name of the Sri Lankan junglefowl is Wali Kukula.

Sexually dimorphic of the Sri Lankan junglefowl, the male is larger than the female, and an exaggerated wattle and comb with a brighter plumage.

The measures of Sri Lankan junglefowl are 790 – 1,140 g (1.74 – 2.51 lb) weighs, and 66 – 72 cm (26 – 28 in) long. It is similar to a large, muscular rooster. Formalized paraphrase The male's body plumage is orange-red, with dark purple to black wings and tail. The golden feathers of the mane descend from the head to the base of the spine, and the face has bare red skin and wattles. The comb is bright red with a yellow center. The cock, like the green junglefowl, does not have eclipse plumage.

The female is much smaller, measuring only 35 cm (14 in) in length and weighing 510–645 g (1.124–1.422 lb), with dull brown plumage and white patterning on the lower belly and breast, making it ideal for nesting.

Gallus is one of four bird species in the genus. Red junglefowl (G. gallus), grey junglefowl (G. sonneratii), and green junglefowl are the other three species in the genus (G. varius).

Although the Sri Lankan junglefowl is similar to the grey junglefowl, the male looks more like the red junglefowl. Female Sri Lanka junglefowls look very similar to grey junglefowls. Sri Lankan junglefowl, like green junglefowl, evolved alongside similarly stranded island predators and competitors. Anti-predator behaviors and foraging strategies that are uniquely complex are essential components of the Sri Lankan junglefowl's long evolutionary story.

It is common in forests and scrub habitats, and can be seen at places like Kitulgala, Yala National Park, and Sinharaja Forest. This species can be found from sea level to 2000 meters in elevation.

Sri Lankan jungle fowl, like other jungle fowl, are mostly terrestrial. They spend the majority of their time scratching the ground for assorted seeds, fallen fruit, and insects to eat.

Females lay two to four eggs in a nest, which they construct on the forest floor in steep hill country or in abandoned bird and squirrel nests. Male Sri Lankan junglefowl, including grey and green junglefowl, actively participate in nest defense and chick rearing.