Saijo (Japanese: 西条市) is a city on the north-central part of Ehime Prefecture, on Shikoku, Japan. It covers 510 sq km (197 sq mi) and has a population of 114,000 people (2012 estimate).
The history of Saijo goes back to 1941. It was built on the site of a natural spring, leading to its claim as the "spring water capital of Japan". Whether or not this is coincidental, but both Coca Cola and Asahi Breweries maintain manufacturing plants in the city. The present limits of Saijo dates to the revision in boundaries in 2004, when Saijo expanded to include the old city of Toyo as well as the towns of Komatsu and Tanbara.