Lysis Of Tarentum (flourished c. 400 bc) was a Greek philosopher and member of the Pythagorean school in southern Italy.
Lysis left Italy for Greece about 390 bc, after escaping a massacre of the Pythagoreans at Croton. Settling in Thebes, he became the teacher of Epaminondas (c. 420–362 bc), the Greek military commander and strategist. The nature of Lysis’ writing is not known, but one source suggests that some works attributed to Pythagoras were actually written by Lysis.