Hosokawa Tama (細川玉?), usually referred to as Hosokawa Garasha (細川ガラシャ?), (1563 – 25 August 1600) was a Japanese samurai woman. She is known for being the daughter of Akechi Mitsuhide, the wife of Hosokawa Tadaoki, and a Christian convert.
She was named Tama at birth; Garasha, the name by which she is known in history, is based upon her Catholic baptismal name, Gracia.
She married Hosokawa Tadaoki at the age of sixteen; the couple had five or six children. In the Sixth Month of 1582, her father Akechi Mitsuhide betrayed and killed his lord, Oda Nobunaga, making the teenage Tama a traitor's daughter. Not wishing to divorce her, Tadaoki sent her to the hamlet of Midono in the mountains of the Tango Peninsula (now in Kyoto Prefecture), where she remained hidden until 1584. Tadaoki then took Tama to the Hosokawa mansion in Osaka, where she remained in confinement.
Tama's maid was from a Catholic family, and her husband repeated to her conversations with his Christian friend Takayama Ukon. In the spring of 1587 Tama managed to secretly visit the Osaka church; a few months later, when she heard that Toyotomi Hideyoshi had issued a proclamation against Christianity, she was determined to be baptized immediately. As she could not leave the house, she was baptized by her maid and received the Christian name "Gracia".