Kingdom of Kosala was an ancient Indian kingdom with a rich culture, corresponding the area with the region of Awadh in present-day Uttar Pradesh to Western Odisha. It emerged as a small state during the late Vedic period, with connections to the neighbouring realm of Videha. Kosala belonged to the Northern Black Polished Ware culture (c. 700–300 BCE), and the Kosala region gave rise to the Sramana movements, including Jainism and Buddhism. It was culturally distinct from the Painted Grey Ware culture of the Vedic period of Kuru-Panchala west of it, following independent development toward urbanisation and the use of iron.

During the 5th century BCE, Kosala incorporated the territory of the Shakya clan, to which the Buddha belonged. According to the Buddhist text Anguttara Nikaya and the Jaina text, the Bhagavati Sutra, Kosala was one of the Solasa (sixteen) Mahajanapadas (powerful realms) in 6th to 5th centuries BCE, and its cultural and political strength earned it the status of a great power. It was later weakened by a series of wars with the neighbouring kingdom of Magadha and, in the 5th century BCE, was finally absorbed by it. After collapse of the Maurya Empire and before the expansion of the Kushan Empire, Kosala was ruled by the Deva dynasty, the Datta dynasty, and the Mitra dynasty.