Despite being close friends, George and Lennie are heavily contrasted both physically and in temperament, serving as foils to each other throughout the novella. These contrasts are emphasized in the first description of the pair in Chapter 1:
Both wore black, shapeless hats and both carried tight blanket rolls slung over their shoulders. The first man was small and quick, dark of face, with restless eyes and sharp, strong features. Every part of him was defined: small, strong hands, slender arms, a thin and bony nose. Behind him walked his opposite, a huge man, shapeless of face, with large, pale eyes, with wide, sloping shoulders; and he walked heavily, dragging his feet a little, the way a bear drags his paws. His arms did not swing at his sides, but hung loosely.