The Sententiae Sexti (Sayings of Sextus) is a collection of ethical advice compiled in Greek during the 2nd century CE. The work is attributed to a figure named Sextus, but this is a pseudonym; the actual compiler or author is unknown. Some ancient readers, like the Christian scholar Origen, thought the sayings came from a Pythagorean philosopher, while others considered them Christian. The date and place of composition are uncertain, but it likely originated in a Greek-speaking region of the Roman Empire where Christian and traditional philosophical ideas mixed.

The work consists of approximately 451 short, moral maxims promoting ideals like self-control, wisdom, purity, and piety. It survives in several ancient languages, including Greek, Latin, Coptic, and Syriac, showing it was widely circulated. Its inclusion in the Nag Hammadi library, a collection of early Christian texts, further indicates its popularity among diverse communities.

Modern scholars see the Sententiae Sexti as a significant example of how early Christian writers adopted and adapted Greek philosophical ethics. The text blends Hellenistic, especially Pythagorean and Stoic, wisdom with a Christian ascetic perspective. Its broad transmission made it an important handbook for moral instruction in late antiquity.