Evan, one of the protagonists in The Lemonade War, is a socially adept young boy who is going into the fourth grade in the fall. Despite his excellent social skills, Evan struggles with feelings of insecurity concerning his academic ability and has trouble with math problems. Over the course of the book, Evan problem solves his way through increasingly difficult challenges until he can solve multi-step word problems.

Evan cares a lot about his younger sister, Jessie, though his jealousy of her academic capacity sometimes gets in the way of their relationship. Though he has friends of his own, he often acts as a caregiver to Jessie. In the past, he told her stories to distract her from their parents’ arguments. In the present, he instructs Jessie in emotional intelligence. He shows empathy and guilt over having lost Jessie’s money and, despite his tendency to get angry with Jessie, is a moral character.

Jessie, the younger of the two protagonists, has just completed second grade and is about to be moved into the fourth grade because of her academic abilities. While she’s able to solve difficult problems quickly and enjoys reading, Jessie struggles to understand social cues and has had difficulty making friends in the past.