Sammy is a 19-year-old clerk working at the local A&P supermarket in a small New England town. As the first-person narrator, he observes his environment with a critical eye, silently judging the regular customers he views as mindless consumers. He feels a growing dissatisfaction with his middle-class life and the conformity expected of him, leading him to construct elaborate fantasies about the people he watches.

"Queenie" is the private nickname Sammy assigns to the confident teenage girl who walks into the supermarket leading two friends. She carries herself with an air of authority that sets her apart from the regular shoppers. To Sammy, she represents the allure and perceived freedom of the upper class, though her actual background and personality remain mostly a product of his imagination.

Lengel is the seasoned manager of the A&P and a firm authority figure in the small town. He enforces the store's policies and represents the traditional, conservative values of the older generation. Serious and rule-bound, he views casual summer attire indoors as an affront to decency and store decorum, functioning as a strict enforcer of the local status quo.

Stokesie is a 22-year-old clerk at the A&P who is married and has two children. Although only three years older than Sammy, his family responsibilities ground him in the reality of his working-class job. He shares Sammy's interest in watching the female customers but polices his own reactions, harboring ambitions to eventually advance within the supermarket's ranks.