Thrasybulus (died 388 BCE) is an Athenian general and democratic leader.

In 411 BCE, in the wake of an oligarchic coup at Athens, the pro-democracy sailors at Samos elect him as a general, making him a primary leader of the successful democratic resistance to that coup.

As general, he is responsible for recalling the controversial nobleman Alcibiades from exile, and the two work together extensively over the next several years.

In 411 and 410, Thrasybulus commands along with Alcibiades and others at several critical Athenian naval victories.

After Athens' defeat in the Peloponnesian War, Thrasybulus leads the democratic resistance to the new oligarchic government, known as the Thirty Tyrants, that the victorious Spartans impose on Athens.

In 404 BCE, he commands a small force of exiles that invades Attica and, in successive battles, defeats first a Spartan garrison and then the forces of the oligarchy.

In the wake of these victories, democracy is reestablished at Athens.

As a leader of this revived democracy in the 4th century BCE, Thrasybulus advocates a policy of resistance to Sparta and seeks to restore Athens' imperial power.

He is killed in 388 BCE while leading an Athenian naval force during the Corinthian War.