George Milton
George is the pragmatic half of the pair. He makes the decisions, handles social situations, and keeps Lennie out of trouble—or tries to. He carries the dream of the farm partly for Lennie and partly because it's the only thing that makes his own hard life feel worth living. His final act defines the whole book.
Lennie Small
Lennie is physically enormous and mentally disabled. He is gentle and loving but has no control over his own strength. He represents innocence that the world cannot accommodate. His obsession with soft things—mice, puppies, Curley's wife's hair—creates the chain of accidents that ends the story.
Candy
Candy is an aging ranch hand who lost his hand in a work accident. He knows the ranch will get rid of him soon, just like his old dog was put down. When he joins George and Lennie's dream, he's buying himself a future. His loss when the dream collapses is as real as George's.
Crooks
Crooks is the Black stable hand who is forced to live separately from the other workers. He is bitter and guarded, but the scenes in his room reveal a man who is deeply lonely and who once dared to hope. He pulls back from the dream when Curley's wife reminds him of his place in this world.
Curley's Wife
She is never given a name, which is itself a statement. She married Curley when her dreams of stardom fell apart, and now she is bored, trapped, and desperate for human contact. The men see her as a threat; Steinbeck shows her as a victim of the same broken world that traps everyone else on the ranch.
Curley
Curley is the boss's son—small, aggressive, and insecure. He picks fights with bigger men to prove himself and treats his wife as property. He functions as the immediate human threat in the story and is the reason George has no time to find another solution when Lennie kills Curley's wife.
Slim
Slim is the most respected man on the ranch—calm, perceptive, and fair. He is one of the few characters who sees George and Lennie's relationship clearly and doesn't mock it. At the end, he's the only one who understands what George has done and offers him something close to comfort.