A tort, in common law jurisdictions, is a civil wrong. Tort law deals with situations where a person's behaviour has unfairly caused someone else to suffer loss or harm. A tort is not necessarily an illegal act but causes harm. The law allows anyone who is harmed to recover their loss. Tort law is different from criminal law, which deals with situations where a person's actions cause harm to society in general. A claim in tort may be brought by anyone who has suffered loss. Criminal cases tend to be brought by the state, although private prosecutions are possible.

Tort law is also differentiated from equity, in which a petitioner complains of a violation of some right. One who commits a tortious act is called a tortfeasor. The equivalent of tort in civil law jurisdictions is delict. Tort may be defined as a personal injury; or as "a civil action other than a breach of contract."

A person who suffers a tortious injury is entitled to receive "damages", usually monetary compensation, from the person or people responsible — or liable — for those injuries. Tort law defines what is a legal injury and, therefore, whether a person may be held liable for an injury they have caused. Legal injuries are not limited to physical injuries. They may also include emotional, economic, or reputational injuries as well as violations of privacy, property, or constitutional rights. Tort cases therefore comprise such varied topics as auto accidents, false imprisonment, defamation, product liability (for defective consumer products), copyright infringement, and environmental pollution (toxic torts), among many others.