A poet, painter, and various merchants of Athens are discussing the things they have prepared for Timon, a wealthy nobleman known for his lavish entertainment. Timon arrives, displaying his generosity by paying a fine on behalf of Ventidius and offering a dowry to his servant Lucilius. Apemantus, a misanthropic observer, warns Timon about his excesses, and tells him that his friends are insincere, but Timon ignores him and throws a lavish party, giving his guests expensive gifts.
His steward Flavius expresses his concern, knowing that Timon is nearly bankrupt. A senator sends his servant to call in a debt from Timon, and other servants join in demanding that their masters’ bills are paid. Flavius finally makes Timon see that he has nothing left, so Timon sends his servants to his friends to ask for help. They approach Lucullus and Lucius, both of whom offer their excuses and deny him, much to the disbelief of some passing strangers. Sempronius also denies him. When everyone starts pressing Timon personally for payment, he decides to hold a final feast for his friends, whom he now recognizes as false. When they arrive at his house he offers them warm water and stones, which he throws at them, driving them away. He then turns his back on Athens. His servants are dismissed, but Flavius expresses a wish to continue as Timon’s steward.
Meanwhile, the Athenian captain Alcibiades has approached the senators asking for mercy to be shown to one of his men who is under sentence of death. The senators refuse to be lenient, and when Alcibiades remonstrates with them they banish him.
Timon finds himself a cave to live in near the shore, and while digging for roots discovers gold. Alcibiades and his army pass by, on his way to taking revenge on Athens, and accompanied by his two mistresses, Phrynia and Timandra. Timon gives them all some gold, enabling Alcibiades to pay his soldiers, but rejects the kindness they display towards him. Apemantus arrives, and there is a bad-tempered discussion of Timon’s situation and their respective characters, before Apemantus is driven away. Bandits visit Timon, and he gives them gold. Flavius also finds him, and Timon recognizes his honesty. The poet and painter come to flatter him, and are also driven away.
Senators arrive offering Timon absolute power in Athens if he will return with them to defend the city against Alcibiades, but he refuses, and anticipates his forthcoming death. The senators plead to Alcibiades, who agrees to spare the city if his enemies are punished. A soldier finds the epitaph Timon has written about himself, and brings it to Alcibiades, who reads it to all as he enters the city.