A Doab, meaning "two waters" is a term used in India and Pakistan for a tract of land between two confluent rivers. The Doab usually refers to a crescent-shaped region of Uttar Pradesh state, in north-central India. It consists of the flat alluvial plain between the Ganges and Yamuna rivers.

The Doab figures strongly in Vedic history and myth. It is the home of many of the earliest Vedic cities and states; the epic Mahabharata is set in the Doab, revolving around the city of Hastinapura.

Each of the tracts between confluent rivers of the Punjab of India and Pakistan has a distinct name, said to have been invented by the Mughal emperor Akbar. They are:

• Sindh Sagar Doab - lies between the Indus and the Jhelum River.
• Chaj Doab - between the Jhelum and the Chenab River.
• Rechna Doab - between the Chenab and the Ravi River.
• Bari Doab - between the Ravi and the Sutlej River.
• Jullunder Doab lies between the Sutlej and the Beas

The Raichur Doab is the triangular region of Andhra Pradesh and Karnataka states which lies between the Krishna River and its tributary the Tungabhadra, named for the town of Raichur.