Chrysippus of Soli was a Greek philosopher of the 3rd century BCE. Born in Soli, Cilicia (in modern-day Turkey), he moved to Athens to study philosophy. There he became a student of Cleanthes, who led the Stoic school founded by Zeno of Citium. Chrysippus succeeded Cleanthes as the third head of the Stoic school around 230 BCE. According to ancient anecdotes, he died at the age of 73, though the colorful story of his death from laughter is likely legendary.

He was an extraordinarily prolific writer. Ancient sources credit him with over 700 works, covering all areas of Stoic thought: logic, physics, and ethics. Titles of his major works include On the Soul and On Providence. However, none of his writings survive intact. They are known only through fragments and summaries quoted by later authors such as Plutarch, Galen, and Diogenes Laertius.

Chrysippus is often called the second founder of Stoicism. His primary historical importance lies in his systematic expansion and defense of the school's doctrines. He developed Stoic logic into a sophisticated system, formulated key theories about language and meaning, and rigorously defended Stoic views on fate and providence against skeptical critics. His work became so central that an ancient saying held, "If there had been no Chrysippus, there would have been no Stoa." His interpretations defined orthodox Stoicism for centuries and established the main target for its opponents.