Daman and Diu is a union territory in western India. With an area of 112 km2 (43 sq mi), it was the smallest federal division of India on the mainland. The territory comprised two distinct regions—Daman and Diu—that are geographically separated by the Gulf of Khambhat.

The state of Gujarat and the Arabian Sea border the territory. A Portuguese colony since the 1500s, the territories were annexed by India in 1961. Daman and Diu were administered as part of the union territory of Goa, Daman and Diu between 1961 and 1987, when they became a separate union territory.

In 2019, legislation was passed to merge the union territory of Daman and Diu with its neighbouring union territory, Dadra and Nagar Haveli, to form the new union territory of Dadra and Nagar Haveli and Daman and Diu. It has also been ruled by Kolis.