Clotho (Greek: Κλωθώ) is the youngest of the Three Fates or Moirai, in ancient Greek mythology. Her Roman equivalent is Nona. Clotho was responsible for spinning the thread of human life. She also made major decisions, such as when a person was born, thus in effect controlling people's lives. This power enabled her not only to choose who was born, but also to decide when gods or mortals were to be saved or put to death. For example, when Pelops was killed and boiled by his father, it was Clotho who brought him back to life.

As one of the three fates her contribution to mythology was immense. Clotho, along with her sisters and Hermes, was given credit for creating the alphabet for their people. Even though Clotho and her sister were real goddesses, their representation of fate is more focused upon in Greek mythology. Thread represented human life and her decisions represented the fate of all men in society.

Clotho was the daughter of Zeus and Themis, and sister to Lachesis and Atropos, according to Greek mythology. Clotho is also mentioned in the tenth book of the Republic of Plato as the daughter of Necessity. In Roman mythology it was believed that she was daughter of Uranus and Gaia. She and her sisters were collectively called the Three Fates.