Strict liability is a legal doctrine in tort law that makes a person responsible for the damages caused by their actions regardless of culpability (fault) or mens rea. The plaintiff needs only to prove that the tort happened and that the defendant was responsible. Neither good faith nor the fact that the defendant took all possible precautions are valid defenses. Strict liability often applies to those engaged in hazardous or inherently dangerous ventures.

A classic example of strict liability is the owner of a tiger rehabilitation center; no matter how strong the tiger cages are, if an animal escapes and causes damage and injury, the owner is held liable. Another example is a contractor hiring a demolition subcontractor that lacks proper insurance. If the subcontractor makes a mistake, the contractor is strictly liable for any damage that occurs.

The law imputes strict liability to situations that it considers to be inherently dangerous. It discourages reckless behavior and needless loss, by forcing potential defendants to take every possible precaution. It also has the effect of simplifying litigation and allowing the victim to become whole more quickly.

The doctrine's most famous advocates were U.S. Supreme Court Justice Benjamin Cardozo and Chief Justice Roger Traynor of the Supreme Court of California.

Defamation is a strict liability tort in many common law jurisdictions like Australia.

In jurisdictions with due process, only the most minor crimes or infractions are subject to strict liability. One example would be parking violations, where the state only needs to show that the defendant's vehicle was parked inappropriately at a certain curb. But serious crimes like rape and murder require some showing of culpability or mens rea. Otherwise, every accidental death, even during medical treatment in good faith, could become grounds for a murder prosecution and a prison sentence.

Strict liability is important in the law of torts, product liability, corporations law, and criminal law.