Justice is an important theme in To Kill a Mockingbird, in which Scout confronts difficult truths about bias and racism within her community. She learns that while the courts can be a potential source of justice, there are also other ways of achieving justice outside the courtroom. This lesson is especially important when she discovers that the legal system does not always return the morally right verdict. In his closing remarks during Tom Robinson’s trial, Atticus tells the jury, “Our courts have their faults, as does any human institution, but in this country our courts are the great levelers, and in our courts all men are created equal.” In this idealized vision, a jury would deliver justice by issuing a decision guided by reason rather than passion. Their judgment would treat all individuals equally, regardless of their race or social circumstance, because equality and lack of prejudice are essential preconditions to justice.

However, the jury finds Tom Robinson guilty even though it was physically impossible for him to commit the crime he’s accused of, which shows that the system is not equal. As Atticus explains to Jem, “The one place where a man ought to get a square deal is in a courtroom, be he any color of the rainbow, but people have a way of carrying their resentments right into a jury box.” When people bring their prejudices into the courtroom, they are unable to make a decision based purely on reason. Even though Atticus suggests the courtroom should be a bastion of justice (“the one place where a man ought to get a square deal”), the failure of the legal system to provide an equal trial suggests that characters must look for other ways to achieve justice. Learning to cope with injustice is an ongoing struggle for the book’s main characters, who must continue to fight for justice even as they recognize the difficulty of their quest.

The novel carefully distinguishes between justice and revenge. In early parts of the book, Scout and Jem are focused on revenge. When their cousin makes a negative comment about Atticus, Scout starts a fight with him; when their elderly neighbor Mrs. Dubose insults Atticus for representing Tom Robinson, Jem tears up all her camellia bushes. However, Atticus teaches the children that these acts of revenge do not actually achieve justice. Instead, he insists that Jem apologize to Mrs. Dubose by reading aloud to her every day. Atticus implies that Jem’s apology and penance make up for the destruction of Mrs. Dubose’s flowers, which suggests that justice is achieved when the guilty person does penance, not when the wronged party returns the negative action as revenge. Bob Ewell’s attempts to seek revenge on the characters he believes humiliated him backfire – Tom Robinson’s widow is protected, the judge is unharmed, and Scout and Jem escape mostly unhurt. Ironically, Bob Ewell is the only character who truly suffers from his desire for revenge, as he is killed by Boo while attacking the children.

The most obvious victim of injustice in To Kill a Mockingbird is Tom Robinson, who is wrongfully convicted for the rape of Mayella Ewell. Although Atticus has hopes for his appeal, Tom is shot and killed while trying to escape prison. His death ensures that he will never receive justice through the legal system. Although many people in Maycomb were against Tom, there are also several people who see his conviction and death as terrible miscarriages of justice. The newspaper runs an editorial calling Tom’s killing a “senseless slaughter,” while Miss Maudie and Aunt Alexandra lament his death. Other members of the community believe that Tom’s conviction sends an important message to the Black community about the negative consequences of seeking equality with whites. While the trial may have changed a few people’s minds in Maycomb, justice for Tom, as well as the Black characters in general, remains unattained. 

The question of whether justice is served in the death of Bob Ewell after Boo Radley kills him to protect the children is open to interpretation. In one sense, Bob’s death serves as punishment for his crime of attacking Scout and Jem, and for his responsibility in Tom Robinson’s death. As the sheriff tells Atticus, “There’s a black boy dead for no reason, and the man responsible for it’s dead. Let the dead bury the dead this time, Mr. Finch.” He decides not to prosecute Boo Radley because he was simply trying to rescue the children, and although Boo would most likely be found innocent, the sheriff does not think justice would be served by bring a shy man so much attention. Atticus eventually accepts that this is the best course of action. When he asks Scout if she understands their decision, she says, “Well, it’d be sort of like shootin’ a mockingbird, wouldn’t it?” This line is a reference to the passage in which Scout learns “it’s a sin to kill a mockingbird” because they are innocent and only exist to help others. Similarly, it would be wrong to prosecute Boo Radley for trying to rescue the children.

Although Bob Ewell’s death provides some semblance of resolution for the novel and ensures that he is punished for his actions, it also distracts the reader from the permanently unresolved tragedy of Tom Robinson’s wrongful conviction. While Bob Ewell’s death may atone for his crime of attacking the children, it does not mitigate the wrongs done to Tom. To Kill a Mockingbird reveals the complexity of justice in episodes such as Mrs. Dubose’s flowers and Bob Ewell’s death, where traditional methods of justice are not employed, but the guilty parties pay penance for their crimes. However, there is no such possibility of redemption to the outcome of Tom’s trial, which is a flagrant miscarriage of justice and is never remedied. As a result, although some forms of justice are achieved through penance or retribution, at the end of the book Tom’s trial remains a lasting injustice that can never be repaired.