The Parallel Lives is a series of 48 biographies of famous men written by the Greco-Roman philosopher, historian, and Apollonian priest Plutarch, probably at the beginning of the second century. It is also known as Plutarch's Lives ; Parallels ; the Comparative Lives ; the Lives of Illustrious Men ; and the Lives of the Noble Greeks and Romans. The lives are arranged in pairs to illuminate their common moral virtues or failings. The surviving Parallel Lives comprises 23 pairs of biographies, each pair consisting of one Greek and one Roman of similar destiny, such as Alexander the Great and Julius Caesar, or Demosthenes and Cicero. It is a work of considerable importance, not only as a source of information about the individuals described, but also about the times in which they lived.

Plutarch was a Greek Middle Platonist philosopher, historian, biographer, essayist, and priest at the Temple of Apollo in Delphi. He is known primarily for his Parallel Lives, a series of biographies of illustrious Greeks and Romans, and Moralia, a collection of essays and speeches. Upon becoming a Roman citizen, he was possibly named Lucius Mestrius Plutarchus.