Negligence (Lat. negligentia) is a failure to exercise appropriate and/or ethical ruled care expected to be exercised amongst specified circumstances. The area of tort law known as negligence involves harm caused by failing to act as a form of carelessness possibly with extenuating circumstances. The core concept of negligence is that people should exercise reasonable care in their actions, by taking account of the potential harm that they might foreseeably cause to other people or property.

Someone who suffers loss caused by another's negligence may be able to sue for damages to compensate for their harm. Such loss may include physical injury, harm to property, psychiatric illness, or economic loss. The law on negligence may be assessed in general terms according to a five-part model which includes the assessment of duty, breach, actual cause, proximate cause, and damages.