Res Judicata – Explained

Cite this article as: Jason Mance Gordon, "Res Judicata – Explained," in The Business Professor, updated January 6, 2015, last accessed March 30, 2020,
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Res Judicata
This video explains what is res judicata and how it limits a plainiff from suing a defendant more than once.



What is “Res Judicata” in civil trials?

Res Judicata is a legal expression meaning that the legal dispute between the parties is decided. This principle prevents successive lawsuits involving the same facts or occurrence. A plaintiff may not sue the defendant for the same conduct under the same or a separate cause of action. The separate cause of action should have been raised during the initial trial. It brings the dispute to a conclusion.

Discussion: Compare the principle or res judicata to the principle of double jeopardy in criminal cases. How are they similar? Different?

Discussion Input

  • The two principles are similar in many ways. In effect, they both prevent the retrial of the same case (or issues in a case) that had previously been heard and determined by the court. The court cannot listen to the matter again if it is based on the same facts or occurrence.

Practice Question: Tom is suing Isabelle for assault. Isabelle allegedly approached Tom in a public restaurant and slapped him in the face. The jury returns a verdict of not liable on the grounds that Isabelle was temporarily incapacitated by rage at seeing her boyfriend having dinner with another woman. Tom is outraged by the verdict and seeks to sue Isabelle a second time for battery. Can Tom sue Isabelle for battery after losing the first trial alleging assault?

Proposed Answer

  • Tom cannot bring an action against Isabelle again. This is based on the doctrine of Res Judicata. An action for battery would be based upon the same conduct that was adjudicated in the prior trial.

Academic Research

Bodart, Bruno, The Social Value of the Doctrine of Res Judicata: An Economic Analysis (May 01, 2018). Available at SSRN: or

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