Matsunaga Hisahide (松永 久秀 1510-November 19, 1577) was a daimyo of Japan.

A companion of Miyoshi Chokei, he was a retainer of Miyoshi Masaga from the 1540s. He directed the conquest of the province of Yamato in the 1560s and by 1564 had build a sufficient power-base to be effectively independent. It is believed that he was conspiring against Chokei during this period, from 1561 to 1563 three of Chokei's brothers died and his son Yoshioki. This left Miyoshi Yoshitsugu the adopted heir when Chokei died in 1564, too young to rule three men shared his guardianship - Miyoshi Nagayuki, Miyoshi Masayasu, and Iwanari Tomomichi.

In 1565 the guardians and Hisahide worked together and dispatched an army to capture Ashikaga Yoshiteru, the shogun, who was then either murdered or forced to commit suicide, he was replaced by the child Yoshihide and the shogun's brother Yoshiaki fled. In 1566 fighting started between Hisahide and the Miyoshi. Initially the forces of Hisahide were unsuccessful and his apparent destruction of the Buddhist Todaiji temple in Nara was considered an act of infamy.

In 1568 Oda Nobunaga, with the figurehead Yoshiaki, attacked Hisahide. Nobunaga captured Kyoto in November and Hisahide was forced to surrender. Yoshiaki was made shogun, a post he held only until 1573 when he attempted to remove himself from Nobunaga's power. Hisahide kept control of the Yamato and served Nobunaga in his extended campaigns against the Miyosi and others, for a while. In 1573 Hisahide briefly allied with the Miyoshi, but when the hoped for successes were not achieved he returned to Nobunaga to fight the Miyoshi. In 1577 he split with Nobunaga again, this time Nobunaga turned on him and besieged him at Shigisan Castle. Defeated but defiant Hisahide committed suicide, he ordered his head destroyed to prevent it becoming a trophy and also destroyed a priceless tea kettle (Hiragumo) that Nobunaga coveted before he died. He reportedly blasted himself and kettle with bags of gunpowder becoming first Japanese to commit suicide through an explosion. His son, Hisamichi, also committed suicide in siege.

Hisahide often appears as a shriveled and scheming old man in a fiction but this is a fictious image from his assasinations and the possible destruction of Todaiji. In truth, he was a tall handsome educated man and a patron of arts. He was also reported to have convereted to Christianity.