Gaius Musonius Rufus was a Roman Stoic philosopher of the 1st century CE. Born into an equestrian family in Etruria, he taught philosophy in Rome. His career was interrupted by several periods of exile under the emperors Nero and Vespasian due to his political associations.

He was a prominent teacher whose students included the philosopher Epictetus. Musonius did not author formal treatises; his teachings survive as a collection of lectures and sayings recorded by his pupils, known as the Discourses. These texts address practical ethical subjects such as marriage, education, diet, and daily conduct. Further fragments of his thought are preserved in the works of other ancient authors.

Modern scholars view Musonius Rufus as a crucial link between earlier Roman Stoics like Seneca and later figures such as Epictetus and Marcus Aurelius. His primary significance lies in his intense focus on applying philosophy to everyday life. He is often noted for his progressive views, particularly his argument that women possess the same natural capacity for virtue and philosophical reasoning as men. His role is interpreted not as that of an original theorist, but as a practical teacher who emphasized living virtuously, an approach that deeply influenced the Stoic tradition.