Scene i: Cassio sends a servant to ask to see Emilia. Iago enters and promises Cassio that he will keep Othello out of the way. Emilia tells Cassio that Desdemona is already pleading his case to Othello, but he still wants to speak with Desdemona. Emilia invites him in.

Scene ii: Othello sends Iago to take care of some official business, and tells him to meet him later to inspect some fortifications.

Scene iii: Desdemona promises Cassio that she will do everything she can for him in getting his job back. Othello and Iago approach and see Cassio with Desdemona. Iago tries to make Othello suspicious with an off-handed comment, but Desdemona, in seeing her husband, declares that it was Cassio she was talking to and argues that Othello should reinstate Cassio. She is bold and Othello listens to her and seems to agree.

When Iago gets Othello alone, he cleverly succeeds in making him believe that Desdemona is having an affair with Cassio. Iago acts as if it pains him to tell Othello this news. He gets Othello to demand he tells him what is on his mind. When Iago says, "Look to your wife," he says it as a friend might. He acts as though he is hurting too. Othello thinks Iago is looking out for him. Iago tells him that Venetian girls are known for their promiscuity, and that Desdemona will eventually realize she would be happier with one her previous WHITE suitors. Othello is a tragic hero. This scene shows his weaknesses. He is easily convinced and terribly jealous. It only takes Iago one scene to talk him into believing his wife is untrue.

Desdemona comes to call Othello to dinner. Desdemona is unstoppable in her pleas to Othello to restore Cassio to his position. She is so relentless it fuels his jealousy even more. Othello says he has a headache, and Desdemona offers him her handkerchief, but Othello pushes it aside and it drops to the floor. Emilia picks up the handkerchief secretly, and gives it to Iago. She reveals that Iago has been asking her to steal it. The handkerchief with the strawberries embroidered on it, will become a major, and symbolic, part of the play.

Othello says he would be happier if he had not known about her infidelities; not knowing for certain is torturing him. Othello threatens Iago saying, "You better prove my love a whore." Iago acts as if he was sorry that he ever told Othello about it. In saying this, Othello calls him back and says he should tell him everything.

Othello returns to Iago, and continues to flare his jealousy. Iago tells him that he has seen Cassio with Desdemona's handkerchief. Othello questions his wife about where her handkerchief if, but she cannot find it. He tells her it has been in his family for generation. He makes up an elaborate story surrounding the handkerchief, including telling her there is magic in it.