Prospero ( PROS-pər-o) is a fictional character and the protagonist of William Shakespeare's play The Tempest. Prospero is the rightful Duke of Milan, whose usurping brother, Antonio, had put him (with his three-year-old daughter, Miranda) to sea on a "rotten carcass" of a boat to die, twelve years before the play begins. Prospero and Miranda had survived and found exile on a small island. He has learned sorcery from books, and uses it while on the island to protect Miranda and control the other characters.

Before the play has begun, Prospero has freed the magical spirit Ariel from entrapment within "a cloven pine". Ariel is beholden to Prospero after he is freed from his imprisonment inside the pine tree. Prospero then takes Ariel as a slave. Prospero's sorcery is sufficiently powerful to control Ariel and other spirits, as well as to alter weather and even raise the dead: "Graves at my command have waked their sleepers, oped, and let 'em forth, by my so potent Art." - Act V, scene 1.

On the island, Prospero becomes master of the monster Caliban (the son of Sycorax, a malevolent witch) and forces Caliban into submission by punishing him with magic if he does not obey.

At the end of the play, Prospero intends to drown his books and renounce magic. In the view of the audience, this may have been required to make the ending unambiguously happy, as magic was associated with diabolical works.