Outside of Lucentio's home in Padua, Lucentio runs off with Bianca and Biondello to the church where he will marry Bianca. Meanwhile, Gremio waits outside Lucentio's door, remarking on how long Cambio is taking to bring Bianca. After Lucentio leaves with Biondello and Bianca, Petruchio arrives with Katherine, Vincentio, and Grumio. Vincentio knocks on the door and asks for Lucentio. The merchant (who is impersonating Vincentio) tells him Lucentio is busy. Petruchio says that Vincentio is Lucentio's father, here to see his son. The merchant denies that Vincentio is Lucentio's father and says that he is, instead.
Now all the disguises and false identities of the play are coming to a head, as the appearance of Vincentio threatens to reveal the deception of Tranio and Lucentio. At the same time, the merchant is so emboldened by his own disguise that he refuses to give in to the reality that he is not Vincentio even when the real Vincentio appears.
Biondello returns from the church, where Lucentio and Bianca have been married. Vincentio recognizes Biondello, but Biondello pretends not to know Vincentio. Vincentio angrily beats Biondello, causing Biondello and the merchant to cry out that a madman is attacking them. Biondello leaves. Baptista and Tranio (still impersonating Lucentio) enter. Vincentio is furious at his servant Tranio when Tranio pretends not to know him. Tranio says that Vincentio is a madman. Baptista is confused and asks Vincentio who he thinks Tranio is. Vincentio identifies him as Tranio, but Tranio continues to say that he is Lucentio. Vincentio thinks that Tranio has murdered Lucentio and stolen his clothes. A police officer arrives and Baptista tells him to carry Vincentio off to jail.
Normally, Vincentio would be able to beat his servant Biondello and discipline Tranio, but all of the mixed-up identities and theatrical disguises of the play have turned these kinds of social standards upside down, such that Vincentio is now at risk of going to jail because no one believes that he is who he actually is. Baptista, much like the reader or audience of Shakespeare's play perhaps, is confused by all the opposing claims of who is who.
Biondello, Lucentio, and Bianca enter. Thinking that their deception has been uncovered and fearing punishment, Biondello, Tranio, and the merchant run away. Lucentio reveals his true identity to Baptista and Vincentio, and explains how he and Tranio changed places. He says that he was motivated by love, and that he and Bianca are now married. Vincentio and Baptista are upset and leave to take out their frustrations on the servants who have deceived them. Lucentio and Bianca exit.
Lucentio reveals his deception, as the numerous disguises of the play unravel. Baptista and Vincentio forgive Lucentio and Bianca, but go to discipline their servants, showing how the rigid social hierarchy, at times subverted by the comedy, has now been re-established.
Petruchio and Katherine, meanwhile, have been watching all this commotion. Katherine suggests they go see how the matter will be resolved. Petruchio says that she must kiss him first. At first, she refuses to kiss him in the middle of the street, so Petruchio threatens to take her back home. Katherine relents and kisses him.
Katherine shows a final flicker of resistance, but ultimately gives in to Petruchio, kissing him in the street.