The Kobayakawa clan (小早川氏, Kobayakawa-shi) was a samurai family of the Sengoku period that owned land in Aki province.
In the mid-16th century they, like the Kikkawa of the same Aki province, became vassals of the powerful Mōri clan that dominated western Japan. The clan fought the Ōtomo of Kyushu for a long time.
They were later, like the Môri, supporters of Toyotomi Hideyoshi, the second unifier of Japan. Kobayakawa Hideaki received the province of Chikuzen as a fief.
At the battle of Sekigahara, the Kobayakawa abandoned the western camp to join Tokugawa Ieyasu and allowed the latter to win. The clan disappeared after the death of Hideaki Kobayakawa, who died without heir in 1602.