Act three scene one opens on the storm raging on Kent, in disguise, talking to a gentleman about how Lear is out in the weather alone, except for the Fool. Apparently, Cordelia has some knowledge of her father's behavior, so Kent asks the gentleman to visit Cordelia and let her know that he is with her father. He gives the gentleman a ring, which proves Kent's identity, so Cordelia will know who he is. Then he tells the gentleman to let him know if he finds the King.

     In scene two Lear is with the Fool in the storm. He notes that the weather doesn't need to treat him well because he hasn't given anything to the weather. Kent finds them and the Fool introduces them as grace and a codpiece, but he notably leaves out which of them is which. Feeling depressed, Lear tells Kent, still in disguise, that he feels he is "more sinned against than sinning," which means he has had worse done to him than he has done to others, a very famous line (King Lear 3.2.60). Kent offers to bring Lear to shelter, so the three of them leave.

     Scene three starts with Gloucester explaining to Edmund that he wanted to assist Lear in finding shelter, but Lear's daughters ordered him not to get involved. He confesses to Edmund that he received a letter about the upcoming battle, and he feels that they need to fight for Lear's side. He doesn't realize, however, that he is giving this information to an enemy. Edmund decides he must tell Cornwall what he knows, so that the young men can take over the elder men's places.

     In scene four Lear is still with Kent and the Fool, and he begins with a stronger moment when he decides that he must stop crying and fight, so he agrees to go into the hovel that Kent has led him to. Having fought against the elements and hunger, Lear sympathizes with the poor and realizes he has not been a good King to the needy people in his land. Then Edgar arrives disguised as Poor Tom. They cover his nakedness with a blanket as Edgar pretends to rant like a crazy person about how he is the "foul fiend" (3.4.52). Lear assumes that this man's daughters must have made him this way because what else could cause a man to become so incoherent. After talking awhile with Edgar, King Lear decides he too should remove his clothing, and he takes a deeper turn into madness. When Gloucester arrives, he does not recognize his own son in his disguise as a beggar. Gloucester tells Kent that Lear's daughters want him dead, and he wishes that good man Kent had not been banished, which is ironic since he says this to Kent. Then he says that he loves his son Edgar while ironically again Edgar is right there listening. These two lines in particular show how blind Gloucester is to what is right in front of his face, part of the motif of blindness.

     In scene five Edmund delivers the letter to Cornwall, and they have a brief conversation about the impending war. In scene six Lear's madness continues. The Fool leaves him, never to return in the play. Gloucester fears for Lear's safety but also wants to go to the cliffs of Dover. When Cornwall and Edmund talk to Regan and Goneril about how Gloucester wants to help protect Lear, Goneril decides they should pluck out Gloucester's eyes for being a traitor. Edmund agrees to this punishment for his father and leaves so that they can carry it out without him witnessing it. When Gloucester comes, Cornwall plucks his eyes out one at a time. A servant jumps in to protect Gloucester and stabs Cornwall, but the servant is killed by Regan. After blinding Gloucester, they allow him to wander off. Cornwall requires assistance because he is bleeding, so Regan helps him exit to end the act.