In Greek mythology, Tethys (Greek: Τηθυς, "nurse" or "grandmother") was one of the Titans and the Titanide of fresh water.
As a Titanide, she was a daughter of Uranus and Gaea. She married her brother, Oceanus, and bore him the Oceanides, the Potamoi, and the Aurae.
The only myth in which Tethys has been mentioned was when Zeus was overthrowing his father, Rhea gave Hera to Oceanus and Tethys for them to care for her.