In Monster by Walter Dean Myers, the theme of justice is explored through the trial of Steve Harmon, a sixteen-year-old African American accused of being an accomplice to murder. The novel delves into the complexities of the justice system, highlighting its flaws and biases, particularly against minority youths. Through Steve's perspective, the narrative examines how justice can be influenced by perceptions, prejudices, and the desire to win at all costs.

The justice system in Monster is portrayed as a powerful antagonist. Steve's lawyer emphasizes the need to humanize him in the eyes of the jury, who may already see him as guilty based on his age, race, and the charges against him. This reflects the real-life prejudices that can affect the fairness of trials. The novel suggests that justice is not always about truth but about who can present the most convincing narrative.

The attorneys in the novel are more concerned with winning the case than seeking true justice. Sandra Petrocelli, the prosecutor, is determined to secure a conviction, even if it means disregarding Steve's actual character. Her opening statement reveals her strategy:

Most people in our community are decent, hardworking citizens who pursue their own interests legally and without infringing on the rights of others. But there are also monsters in our communities—people who are willing to steal and to kill, people who disregard the rights of others.

This approach highlights the adversarial nature of the legal system, where the focus is often on victory rather than fairness.

Steve's internal struggle with his identity further complicates the theme of justice. Throughout the trial, he grapples with the label of "monster" imposed on him by the prosecutor. This reflects the dehumanizing effect of the justice system, which can strip individuals of their identity and reduce them to stereotypes. Steve's journey is not just about proving his innocence but also about reclaiming his sense of self.

The novel also raises questions about the fallibility of the justice system. It suggests that errors can occur, and innocent people can be wrongly convicted, particularly those without resources or societal support. This is a stark reminder of the system's potential to fail those it is meant to protect, emphasizing the need for objectivity and fairness in legal proceedings.