Guilt is a central theme in The Crucible, manifesting through characters' actions and motivations. The play explores the complex interplay between legal guilt and moral guilt, highlighting how guilt can lead to irrational behavior and societal chaos. In the Puritan society depicted in the play, the presumption of guilt replaces the presumption of innocence, leading to a flawed judicial process. This theme is reflected in the characters' struggles with their own guilt and the consequences of their actions.

The dichotomy between legal and moral guilt is evident in the trials, where individuals are accused of witchcraft, a crime that cannot be proven. The Puritan belief in original sin means that everyone is presumed guilty, as no one is pure in the eyes of God. This is illustrated in Act III, when Judge Hathorne questions Martha Corey, expecting her to prove her innocence rather than the court proving her guilt. Reverend Hale's suggestion that John Proctor should have a lawyer is dismissed by Danforth, who claims that witchcraft is an invisible crime, relying solely on the victim's testimony. This flawed system ensures that defendants are found guilty, aligning with Puritan theology.

John Proctor's internal struggle with guilt is a key aspect of the play. His affair with Abigail Williams leaves him feeling guilty and lacking integrity. Proctor desires to regain his self-respect and the trust of his wife, Elizabeth. He ultimately chooses to die rather than sign a false confession, valuing his dignity over life. Elizabeth, in turn, acknowledges her role in their strained relationship, expressing regret for her coldness and seeking to alleviate John's guilt.

Reverend Hale's guilt is another significant element. He returns to the jail to persuade the condemned to confess to crimes they did not commit, hoping to save their lives. Hale feels guilty for his role in the witch trials and the deaths of innocent people. He refers to the "blood on [his] head," acknowledging his responsibility for the tragedy. His guilt drives him to try to rectify the situation, even if it means encouraging lies to save lives.