The key events in To Kill a Mockingbird are driven by the undercurrent of prejudice that runs through Maycomb. The most obvious victim of this prejudice is Tom Robinson, a Black man falsely accused of raping a white woman. Tom’s conviction is all but assured—despite the obvious inaccuracies and impossibilities of Mayella’s accusation—illustrating the depth of racism in the town. Tom’s accuser, Mayella Ewell, faces prejudice of a different sort. The Ewell family is considered "white trash” by the rest of the town. Aware of their lowly reputation, Bob Ewell’s persecution of Tom is driven in part by a desire to assert power over the only group in Maycomb with less social status than the Ewells. 

Though Scout is firmly entrenched in the white world of Maycomb, we get a small glimpse of life for Maycomb’s Black community when Scout visits Calpurnia’s run-down church. The visit is marred by a confrontation between Calpurnia and Lula, who argue over whether the children should be allowed to come to a Black church. Though the rest of the church is welcoming, Lula’s anger at their presence speaks to the inherent unfairness of the situation: the white Finches—while well-meaning—may enter and leave both Black and white spaces freely, a luxury that Lula and the other Black people in Maycomb do not possess.

The rampant racism in Maycomb bleeds into the personal lives of the Finch family when Atticus becomes Tom Robinson’s defense attorney, prompting a swift social backlash from many white neighbors. When their aunt comes to visit, Scout and Jem witness prejudice within their own family as well: Aunt Alexandra not only encourages Atticus to fire Calpurnia, but also urges him to teach Jem and Scout about the importance of heritage and class. While many citizens of Maycomb hold strong racist and classist assumptions like Alexandra does, these individuals are contrasted against characters like Atticus and Miss Maudie, who choose to judge people by their character rather than their background or race. This is a lesson that both Scout and Jem learn firsthand through their interactions with Boo Radley. Though they initially fear Boo due to his obscurity and the rumors about him in town, the children eventually come to realize that he, too, is a victim of prejudice; instead of trying to understand him, the townspeople have solidified his outsider status.