Hōanji temple ruins (法安寺跡) is an archaeological site with the ruins of a Hakuho period Buddhist temple located in the Komatsu neighbourhood of what is now the city of Saijō, Ehime, Japan. The actual name of the temple is unknown, as it does not appear in historical records, and the site takes its name from a later Shingon temple named Hōan-ji which was built on top its ruins. The Asuka period temple remnants were designated as a National Historic Site in 1944, with the area under designation expanded in 1969.