Othello
A Moor, and an officer in the Venetian military. He falls in love with, and marries, the delicate Desdemona though he is middle-aged, and she is still young. Othello is bold and a good warrior, but he is a good man undone by his two main failings - jealousy and pride. Although Othello is very eloquent, he believes his manners and words are both rough.
Desdemona
Othello's wife, a young Venetian woman of high birth and good breeding. Desdemona is almost overly virtuous, which causes her to feel that she must defend Cassio, and speak in a public sphere when necessary. She is stronger than Othello believes her to be, and is not the private, withdrawn, meek woman he wish she were.
Cassio
Othello's lieutenant, though he has little field experience. Cassio is a smooth-talking Venetian courtier, the opposite of Othello in many respects, which is why Othello admires him. Othello is led to believe that Cassio has had an affair with his wife, though Cassio has only honorable intentions toward Desdemona.
Iago
Othello's ensign who was passed over for the lieutenant position in favor of Cassio. Iago is young and treacherous; he is a villain from the start, and though he cites his wounded pride and Othello's alleged infidelity with his wife Emilia, his actions are without justification. He is immoral, but very perceptive, keen, and able to manipulate people into falling for his deceptions.
Emilia
Iago's wife, and Desdemona's handmaiden. She is entrusted with bringing people into Desdemona's presence, staying with her at all times, etc. Emilia is not aware of her husband's machinations, nor his darker qualities. She remains loyal to Desdemona above all others, although she unwittingly plays a key part in Iago's treachery.
Brabantio
Desdemona's father, a senator and renowned citizen of Venice. He is not at all pleased by Desdemona's union, and warns Othello that as Desdemona betrayed her father, she may betray her husband too.
Roderigo
A Venetian who lusts after Desdemona, and thus a tool in Iago's plots. Iago promises Roderigo that he shall have Desdemona's love in return for his help; Roderigo actually receives nothing but a disgraced death following his attempt on Cassio's life.
Duke of Venice
Ruler of the city, and Othello's superior. He allows Othello and Desdemona to stay together despite her father's protests. The Duke also sends Othello off to Cyprus to battle the Moors.
Senators
Other authority figures of Venice, and men of reason and order; they also support Othello and Desdemona's union, and Othello answers to them and the Duke in matters of war.
Bianca
A courtesan who Cassio visits frequently; Cassio asks her to make a copy of Desdemona's handkerchief, and the fact that the handkerchief is found in her place further incriminates Cassio. She is the only female in the play whom Cassio shows less than full respect to, likely because she is a prostitute.
Montano, Governor of Cyprus
Pronounces judgment on Iago at the end of the play, comments on the situation, and helps to wrap the play up. He is the main law and order figure of Cyprus, and serves as damage control after Othello dies, and Iago is proven unfit.
Lodovico and Gratiano
Two Venetian nobles, both of some relation to Desdemona; both play their biggest part after Desdemona has died, and must take the news of the tragedy back to Venice as officials of that city.