Esperanza Cordero is the oldest of four children. Her age is never explicitly stated in the text, but she is somewhere between childhood and the teenage years, perhaps 13. She and her family live on Mango Street, an urban neighborhood in a city resembling Chicago. Esperanza feels confined by the primarily Latino neighborhood, and she is eager to grow up so she can move away and find a place that feels more like home. She hopes to be a writer someday, and she shares her love of books and poetry with her friends in the neighborhood. Esperanza doesn't discriminate when it comes to selecting friends; she is just as likely to forge relationships with the outcasts as she is the popular kids. She isn't as concerned with appearances as some of her friends, and she has a knack for seeing the goodness that resides in those who might otherwise be ignored. A friend to almost everyone she meets, Esperanza is slightly wary around the older neighborhood boys. She is torn between wanting them to notice her and wanting to blend in with the rest of the neighborhood kids. At this crucial stage of adolescence, she is still trying to figure out where childhood ends, where adulthood begins, and which side of the divide she wants to be on.
Nenny Cordero is the youngest of the Cordero children. It is Esperanza's responsibility to look out for her younger sister when they are in the neighborhood, and as such she considers Nenny to be more of a responsibility than a friend. Esperanza is sometimes embarrassed by Nenny's childlike behavior, but there are also times when she welcomes Nenny's point of view (usually when it aligns with her own).
Sally is around the same age as Esperanza, but their maturity levels are quite a bit different. While Esperanza still wants to play games with the younger neighborhood kids, Sally is focused on attracting the attention of the teenage boys. This isn't hard, as Sally (according to Esperanza) is gorgeous, with her long black hair and "eyes like Egypt." Sally's father also recognizes his daughter's attractiveness, which is why he insists she be home when she's not at school. His protection hasn't helped; Sally has a reputation among the boys at school. Esperanza wants to be Sally's friend because she thinks they both want more out of life than the barrio can offer them, but it turns out Sally just wants to leave her father's home, even if it means getting married before she's in high school.
Rachel is younger than her sister Lucy, but she's far more gregarious. She does all the talking for the pair, and she is the one who first approaches Esperanza in search of five dollars so she and Lucy can buy a bike from Tito. Rachel is too young to know to be cautious around older men, and she starts chatting up the bum in front of the tavern without a second thought. Were it not for Lucy's intervention, Rachel probably would have kissed him just to earn an extra dollar.
Lucy is the quieter of the two sisters, but like Esperanza, she looks out for her younger sibling. She drags Rachel away from the bum sitting in front of the tavern, and she hides the high heels underneath the porch so they can't get the girls into any more trouble. Esperanza really likes Lucy, but she seems to forget about her and Rachel when Sally comes along.
Marin is about Esperanza's age but sees herself as much more sophisticated. She was sent from her home in Puerto Rico to live with her cousin's family in Chicago. She sells makeup and spends much of her time sharing wisdom about boys and feminine wiles. Her cousin's family considers her a bad influence and sends her back to Puerto Rico after a year.