The Chestnut-breasted Partridge (Arborophila mandellii) is a species of partridge endemic to the eastern Himalayas north of the Brahmaputra, and is known from Bhutan, West Bengal (Darjeeling only), Sikkim and Arunachal Pradesh, north-east India, and south-east Tibet.

It is a distinctive partridge with chestnut breast-band and grey belly. It is distinguished from the similar Rufous-throated Partridge A. rufogularis by more rufescent crown and head-sides, white gorget and entirely chestnut upper breast.

This bird has been classified as Vulnerable, with an estimated population of less than 10,000. It is threatened by forest degradation, which is fragmenting the population, and by hunting. It is known from at least three protected areas, including Singalila National Park (West Bengal).