De Brevitate Vitae (English: On the Shortness of Life) is a moral essay written by Seneca the Younger, a Roman Stoic philosopher, sometime around the year 49 AD, to his father-in-law Paulinus.

It is clear from chapters 18 and 19 of De Brevitate Vitae that Paulinus was praefectus annonae, the official who superintended the grain supply of Rome, and was, therefore, a man of importance.

A date of 49 AD has previously been suggested because Seneca writes in §13.8 "that Sulla was the last of the Romans who extended the pomerium" (the boundary of Rome).

Griffin has suggested that Seneca wrote De Brevitate Vitae as an excuse for Paulinus to retire early in 55 AD.

He then offers (§4–6) three examples of famous Romans (Augustus, Cicero and Livius Drusus) who, in various ways, were victims of the engrossed life.

The engrossed include those who live in leisure and luxury (§12), and Seneca explains (§13) that even those who devote themselves to scholarship are wasting their time if their efforts are directed to no end.

Finally (§18–19) Seneca exhorts Paulinus to abandon public occupations and adopt the contemplative life of the wise, free from the passions.

Wise people, on the other hand, understand that time is the most valuable of all resources, and with effort can free themselves from external control to engage in meaningful introspection and create an intentional life.

The completeness of each present moment allows one's awareness to expand to the equal of that of the universe, and achieve true virtue and happiness.