The act begins with Higgins, Pickering, and Eliza returning to Higgin’s home around midnight from the ball. With a tired Eliza sitting unnoticed and silent in the room, Pickering and Higgins discuss the bet. Pickering congratulates Higgins and only Higgins, who scoffs and dismisses the entire experiment as silly and boring. Higgins declares his relief at being done with it, as he grew sick of the whole thing two months ago. As the men are leaving, Higgins only briefly acknowledges Eliza, asking her to tell Mrs. Pearce to make tea instead of coffee.

Looking for his slippers, Higgins returns to the drawing room. Enraged at being ignored and worried about her future now that the experiment is over, Eliza throws his slippers at him. Higgins is unable to understand her concern and is taken aback by what he perceives as her bad manners and ingratitude. Once Higgins understands her concern, he mocks it, saying she should get married. Eliza interprets this as Higgins suggesting she should sell herself.

When Higgins goes to leave, Eliza pointedly asks if her clothes belong to her or to Higgins and Pickering to use on the next girl they experiment on. Higgins tells her that everything belongs to her except for the rented jewelry.