Slim is a handsome, strong, intelligent and decent man who is a natural leader with 'gravity', a good listener and respected by the ranch hands.

George is small and quick, a restless, clean-living, intelligent man who is very caring and modest, a strong personality but unhappy with his life.

Lennie is big and strong, a man with a child's mind who depends on George. He loves to stroke animals but cannot control his strength.

Curley is the Boss's son, who is needlessly aggressive, arrogant and selfish, and is always spoiling for a fight.

She is a flirtatious, attractive and lonely girl who regrets marrying Curley, and who is accidentally killed by Lennie.