Mahājanapadas, literally "great realms", (from maha, "great", and janapada "foothold of a tribe", "country") are ancient Indian kingdoms or countries.

Ancient Buddhist texts like Anguttara Nikaya make frequent reference to sixteen great kingdoms and republics (Solas Mahajanapadas) which had evolved and flourished in a belt stretching from Gandhara in the northwest to Anga in the eastern part of the Indian subcontinent and included parts of the trans-Vindhyan region, prior to the rise of Buddhism in India.

The sixth century BCE is often regarded as a major turning point in early Indian history.