Antiphon was an Athenian intellectual active in the late 5th century BCE. He is traditionally identified as a sophist, a teacher of rhetoric, and a professional speechwriter who composed legal arguments for others to deliver in court. According to modern scholars, he is a complex figure because ancient sources may refer to more than one person with this name. The prevailing view today is that the speechwriter, the sophist philosopher, and the oligarchic politician were the same individual.

His surviving works fall into two categories. Three complete courtroom speeches survive, which are the earliest examples of Athenian forensic oratory. He also wrote philosophical works and rhetorical exercises, known as the Tetralogies, which explore legal principles and arguments. Fragments of his treatises, such as On Truth, contain sophisticated discussions on nature, justice, and human convention.

Politically, Antiphon was a leading member of the oligarchic government known as the Four Hundred, which briefly overthrew the Athenian democracy in 411 BCE. After the democracy was restored, he was tried for treason, convicted, and executed. The historian Thucydides praised his defense speech, though it has not survived.

Antiphon is considered a foundational figure in the history of rhetoric, often called the first Athenian speechwriter whose works survive. His writings provide crucial insight into Athenian law, society, and the intellectual debates of the Sophistic movement during the Peloponnesian War.