Lennie Small A migrant worker who is mentally handicapped, large, and very strong. He depends on his friend George to give him advice and protect him in situations he does not understand. His enormous strength and his pleasure in petting soft animals are a dangerous combination. He shares the dream of owning a farm with George, but he does not understand the implications of that dream.
George Milton A migrant worker who protects and cares for Lennie. George dreams of some day owning his own land, but he realizes the difficulty of making this dream come true. Lennie's friend, George gives the big man advice and tries to watch out for him, ultimately taking responsibility for not only his life but also his death.
Slim The the leader of the mule team whom everyone respects. Slim becomes an ally to George and helps protect Lennie when he gets in trouble with Curley. Slim has compassion and insight, and he understands George and Lennie's situation. He alone realizes, at the end of the novel, the reason for George's decision.
Candy Sometimes called "the swamper," he is a old handyman who lost his hand in a ranch accident and is kept on the payroll. Afraid that he will eventually be fired when he can no longer do his chores, he convinces George to let him join their dream of a farm because he can bring the necessary money to the scheme. He owns an old sheep dog that will become a symbol of Lennie before the novel ends.
Crooks The black stable worker who cares for the horses. A symbol of racial injustice, Crooks is isolated from the other hands because of his skin color. He also convinces Lennie to let him join their dream of land, but he must give up that dream.
Carlson The insensitive ranch hand who shoots Candy's dog. He owns a Luger, which George later uses to mercifully kill Lennie.
Curley The son of the ranch owner, Curley is a mean little guy who picks fights with bigger guys like Lennie. He is recently married and extremely jealous of any man who looks at or talks with his wife. Lennie crushes his hand, earning Curley's future enmity.
Curley's wife The only character in the novel who is given no name, she is Curley's possession. She taunts and provokes the ranch hands into talking with her, an action that causes Curley to beat them up. George sees her as a "tart," but Lennie is fascinated by her soft hair and looks. She is unsympathetically portrayed as a female tease until the final scene, in which the reader hears about her earlier dreams. Lonely and restless, she married too quickly to a husband who neglects her.