Theramenes (d. 404 BC, Greek: Θηραμένης) was an Athenian statesman, prominent in the final decade of the Peloponnesian War. He is particularly active during the two periods of oligarchic government at Athens, as well as in the trial of the generals who had commanded at Arginusae in 408 BC. A moderate oligarch, he often found himself caught between the democrats on the one hand and the extreme oligarchs on the other. Successful in replacing a narrow oligarchy with a broader one in 411 BC, he failed to achieve the same end in 404 BC, and was executed by the extremists whose policies he had opposed.

Theramenes was a central figure in four major episodes of Athenian history. He appeared on the scene in 411 BC as one of the leaders of an oligarchic coup, but, as his views and those of the coup's other leaders diverged, he began to oppose their dictates and took the lead in replacing the narrow oligarchy they had imposed with a more broadly based one. He served as a general for several years after this, but was not reelected to that office in 407 BC. After the Battle of Arginusae, in which he served as a trierarch, he was assigned to rescue Athenian sailors from sinking ships, but was prevented from doing so by a storm.