Sagamihara (相模原市, Sagamihara-shi^?) is a city located in north central Kanagawa Prefecture, bordering Tokyo, Japan. It is the third most populous city in the prefecture, after Yokohama and Kawasaki, and the fifth most populous suburb of Greater Tokyo. Its northern neighbor is Machida, with which a cross-prefectural merger has been proposed. As of 2010, the city has an estimated population of 712,883 and a population density of 2,170 persons per km². The total area was 328.84 km².

On April 1, 2010, the city became the nation's 19th city designated by government ordinance. As a result of this, the city established three wards: Midori-ku, Chūō-ku and Minami-ku.

Sagamihara covers a large area of northwestern Kanagawa Prefecture. The main areas of commercial activity in Sagamihara are located near Hashimoto Station on the JR East Yokohama Line and Keio Sagamihara Line; Sagamihara Station on the Yokohama Line; and Sagami-Ōno Station on the Odakyū Odawara Line. Western Sagamihara is within the Tanzawa Mountains.