Sainoo temple ruins (斎尾廃寺跡, Sai-no-o Haiji ato) is an archeological site with the ruins of a Hakuhō period Buddhist temple located in the Tsukishita neighborhood of the town of Kotoura, Tottori prefecture, in the San'in region of Japan.

Within are foundation stones indicating that the temple had a layout patterned after Hōryū-ji in Ikaruga, Nara, orientated to the south, with a pagoda to the west and the Kondō to the east.

Archaeological excavations have found the foundations of the Middle Gate, cloisters and the bell tower.

A reproduction model of the temple and some of the excavated items are displayed at Kotoura Town Adult Learning Center "Manabi Town Tohaku" and Hakuhokan Museum near the site.

[2] The site is about ten minutes by car from Urayasu Station on the JR West San'in Main Line.