Timon of Phlius (ˈtaɪmən ; Tímōn ho Phliásios, () Τίμωνος, ; 320 BC - c. 235 BC) was an Ancient Greek philosopher from the Hellenistic period, who was the student of Pyrrho. Unlike Pyrrho, who wrote nothing, Timon wrote satirical philosophical poetry called Silloi (Σίλλοι) as well as a number of prose writings. These have been lost, but the fragments quoted in later authors allow a rough outline of his philosophy to be reconstructed.
The primary source for Timon's biography is the account in Diogenes Laërtius, which claims to be taken from earlier authors such as Apollonides of Nicaea, Antigonus of Carystus, and Sotion, whose works have now been lost. According to Diogenes, Timon was born in Phlius, and was at first a dancer in the theatre, but he abandoned this profession for the study of philosophy, and, having moved to Megara, he spent some time with Stilpo, returned home to marry, and then moved to Elis with his wife, and heard Pyrrho, whose tenets he adopted. Driven again from Elis by straitened circumstances, he spent some time on the Hellespont and the Propontis, and taught at Chalcedon as a sophist with such success that he made a fortune. He then moved to Athens, where he lived until his death, with the exception of a short residence at Thebes. According to Diogenes he knew the kings Antigonus and Ptolemy II Philadelphus. The Suda also claims he was linked to several literary figures such as: Alexander Aetolus and Homerus, whom he is said to have assisted in the composition of their tragedies; and Aratus, whom he is said to have taught. He died at an age of almost ninety.
According to Diogenes Laërtius, Timon composed "lyric and epic poems, and tragedies and satiric dramas, and thirty comedies, and sixty tragedies and the Silloi and amatory poems." The Silloi has not survived intact, but they are mentioned and quoted by several ancient authors. It has been suggested that Pyrrhonism ultimately originated with Timon rather than Pyrrho.