Critias (; , Kritias; c. 460 – 403 BCE) was an ancient Athenian political figure and author. Born in Athens, Critias was the son of Callaeschrus and a first cousin of Plato's mother Perictione, and became a leading and violent member of the Thirty Tyrants. He was an associate of Socrates, a fact that did not endear Socrates to the Athenian public.