Res judicata
From Roman law, in both traditions
Procedure and evidence
What it means
The rule that a matter that has been finally decided cannot be argued again between the same parties. It protects the finality of judgments.
Why it travels badly
The Latin label is the same, but the reach differs. Common law has several related rules: claim preclusion, issue estoppel and abuse of process. Civil law is generally narrower: finality attaches to what the court decided, not to the reasons it gave.
How other systems say it
claim preclusion and issue preclusion
A final judgment bars a second claim on the same cause of action, and bars re-argument of issues actually decided.
res judicata, issue estoppel, abuse of process
Includes the rule in Henderson v Henderson that a party should bring the whole of their case at once.
autorité de la chose jugée (art 1355 Code civil)
Applies only where the same parties bring a claim with the same object and the same cause.
Rechtskraft (§ 322 ZPO)
The judgment is final only as to the claim decided, not as to the reasons in it.
Tip for translators and students
In translation, say whether the effect covers the issues decided or only the final order. The label alone does not tell the reader.
Related: Estoppel, Stare decisis and jurisprudence constante
Updated October 2026. Spotted a mistake? Tell us.
TheLawToKnow Tools’s glossary is an educational overview of the main differences between legal systems. It is not legal advice.
