In Greek mythology, Jocasta, also Iocaste or Epikastê, was a daughter of Menocenes. She was the wife of Laius and, by him, mother (and wife) of Oedipus, and mother (by Oedipus) of Antigone, Eteocles, Polynices and Ismene.

Her husband, King Laius of Thebes, consulted an oracle when she was pregnant with her first child, Oedipus. The oracle claimed he was destined to kill his father and marry his own mother. Laius had the baby left out in the woods to die. He was found by a shepherd and given to King Polybus and Queen Merope (or Periboea) of Corinth.

Later, Oedipus killed Laius, not knowing who he was, and married Jocasta, not knowing who she was. When this was discovered, Oedipus tore out his own eyes and Jocasta committed suicide by hanging.

See also: Oedipus the King by Sophocles.

In astronomy, Iocaste is the name of a small moon of the planet Jupiter.