Ōuchi Yoshioki (大内 義興, April 7, 1477 – January 29, 1528) was a samurai of the Ōuchi family who lived during Japan's early Sengoku period. He is famous for his role in restoring the Shogun Ashikaga Yoshitane to power in 1508, and in building Saijō castle.
Ashikaga Yoshitane had been forced to flee Kyoto in 1490, after resisting efforts by Kanrei (Shogunal Deputy) Hosokawa Katsumoto to control him as a puppet ruler. Ōuchi Yoshioki rose to his aid in 1507, gathering an army and marching on the capital, fighting his way through a great number of other samurai families along the way. Katsumoto's son and successor, Hosokawa Masamoto, was killed, and his puppet shogun Ashikaga Yoshizumi removed. Awarded the fourth rank in the Imperial Court, Ōuchi remained in the capital, protecting Yoshitane, and supporting him and the Emperor financially, until 1518, when he returned to his family's home in Yamaguchi.
- Sansom, George (1961). "A History of Japan: 1334–1615." Stanford, California: Stanford University Press.
- Turnbull, Stephen (1998). The Samurai Sourcebook. London: Cassell & Co.