It is finally time for Lucentio and Bianca's wedding banquet. Baptista, Vincentio, Gremio, the merchant who had pretended to be Vincentio, Lucentio, Bianca, Petruchio, and Katherine are all present. The servants Tranio, Grumio, and Biondello are there as well, as are Hortensio and the widow he has married. Lucentio welcomes everyone to the banquet, calls Petruchio and Katherine his brother and sister, and says that all the earlier chaos and confusion is now happily resolved.
While Lucentio and Bianca eloped to marry out of love, their wedding banquet firmly establishes their marriage as a social event bringing together different families.
As the guests at the banquet trade jokes and jibes, the widow teases Petruchio for being married to a shrew, offending Katherine. The women leave, and Tranio also teases Petruchio, saying he is ruled by his wife. Baptista tells Petruchio that he has "the veriest shrew of all," (v.2.66).
The characters who have not seen Katherine's apparent transformation, continue to heap their usual abuse on her, insulting her for her resistance to male authority.
In response to all this teasing, Petruchio proposes a bet. He, Lucentio, and Hortensio will call their wives, and the husband whose wife comes first will win a wager of money. Lucentio sends Biondello to fetch Bianca, but he returns with the news that she says she is busy and won't come. Hortensio then sends Biondello to get the widow, but she refuses to come, as well.
Petruchio's bet shows how important he thinks a wife's obedience is in marriage. The other husbands are surprised to find that they are not as powerful in their marriages as they thought they were, and that their wives may have a bit of Katherine's nerve, as well.
Petruchio tells Grumio to find Katherine and tell her that Petruchio commands her to come to him. Grumio goes to get her and, to the surprise of everyone but Petruchio, she comes immediately. Petruchio orders her to go and bring the other wives to them, and she obeys.
Katherine, in contrast to Bianca and the widow, is entirely devoted to Petruchio. But it is still possible that she is simply performing the role of a subservient wife, perhaps even in cahoots with Petruchio to win the bet.
The men are amazed at Katherine's obedience. Baptista says that Petruchio has won the bet, and jokes that he'll give him even more money as a second dowry, since Katherine is now a completely different daughter. Katherine returns with Bianca and the widow. Lucentio chides Bianca for not coming, telling her that her disobedience cost him money. Bianca replies that it was his fault for betting the money.
Regardless of how real Katherine's transformation is, the other characters believe that it is genuine. Lucentio tries to show some authority in chastising Bianca, but she shows that she has a will of her own, and is not merely a passive wife.
Petruchio asks Kate to tell the other wives what duty they owe to their husbands. The widow protests, but Petruchio insists on it. Katherine begins a long speech, detailing the importance of a wife's submission to her husband. She tells the wives, "Thy husband is thy lord, thy life, thy keeper, / Thy head, thy sovereign," (v.2.162-163). She says that a wife owes her husband "love, fair looks, and true obedience," (v.2.169) and that women are bound to "serve, love, and obey," (v.2.180). Petruchio is pleased with her speech and asks her to kiss him, which she does. As they leave together to go to bed, Hortensio and Lucentio marvel at Petruchio's ability to tame Katherine.
Katherine's long speech is perhaps the most controversial part of the play. How can the strong-willed Katherine expound at such absurd length the duties of a docile, submissive wife? Has she really been so tamed, or is she pulling one over on the other characters? Depending on the choices a particular production of the play makes, Katherine's speech can be seen as ironically over the top or startlingly sincere. Whether she means it or not, her speech outlines the essential qualities of a good wife according to traditional, oppressive gender roles.