One of the main themes of the play "Trifles" is the way in which gender and power dynamics can shape the way that people perceive and understand events. The play explores the ways in which the men in the story, who are in positions of power and authority, are quick to jump to conclusions and overlook important clues, while the women, who are marginalized and dismissed, are able to see and understand the subtler aspects of the situation. The play suggests that the men's assumptions and prejudices about women prevent them from fully grasping the truth of what happened in the Wright farmhouse and that it is ultimately the women who are able to solve the mystery.

Another theme of the play is the impact of domestic violence and abuse on the lives of women. The play suggests that Mrs. Wright was driven to kill her husband in self-defense after years of abuse and that the men in the story are unable to understand or recognize the signs of this abuse because they are not attuned to the emotional lives of the women around them.

Other themes of the play include justice, the role of the legal system, and the ways in which social and cultural factors can shape the way that people behave and perceive the world.