Ishida Mitsunari (石田 三成, 1559 – November 6, 1600) was a Japanese samurai and military commander of the late Sengoku period of Japan. He is probably best remembered as the commander of the Western army in the Battle of Sekigahara following the Azuchi–Momoyama period of the 16th century. He is also known by his court title, Jibu-no-shō (治部少輔).