Attalus (/ˈætələs/ AT-əl-əs; Greek: Ἄτταλος) was a Stoic philosopher in the reign of Tiberius around 25 AD. He was defrauded of his property by Sejanus, and exiled where he was reduced to cultivating the ground.^[1] The elder Seneca describes him as a man of great eloquence, and by far the acutest philosopher of his age.^[1]

He taught the Stoic philosophy to Seneca the Younger,^[2] who frequently quotes him, and speaks of him in the highest terms.^[3] Seneca reminisces about Attalus in his 108th Letter:

This was the advice, I remember, which Attalus gave me in the days when I practically laid siege to his class-room, the first to arrive and the last to leave. Even as he paced up and down, I would challenge him to various discussions; for he not only kept himself accessible to his pupils, but met them half-way. His words were: "The same purpose should possess both master and scholar – an ambition in the one case to promote, and in the other to progress."

In the same letter, Seneca describes some of the Stoic training he received from Attalus:

And in truth, when he began to uphold poverty, and to show what a useless and dangerous burden was everything that passed the measure of our need, I often desired to leave his lecture-room a poor man. Whenever he castigated our pleasure-seeking lives, and extolled personal purity, moderation in diet, and a mind free from unnecessary, not to speak of unlawful, pleasures, the desire came upon me to limit my food and drink.

Of his written works, none survive. Seneca mentions a work of his on lightning;^[4] and it is supposed that he may be the author of the Proverbs referred to by Hesychius^[5] as written by one Attalus.