Products liability refers to the liability of any or all parties along the chain of manufacture of any product for damage caused by that product. This includes the manufacturer of component parts, an assembling manufacturer, the wholesaler, and the retail store owner. Product liability suits may be brought by the consumer or someone to whom the product was loaned. While products are generally thought of as tangible personal property, products liability law has stretched that definition to include intangibles (gas), naturals (pets), real estate (house), and writings (navigational charts).

Products liability claims can be based on negligence, strict liability, or breach of warranty of fitness depending on the jurisdiction within which the claim is based. In a strict liability theory of liability, the degree of care exercised by the manufacturer is irrelevant. As long as the product is proven to be defective, the manufacturer will be held liable for the harm resulting from the defect.

Claims may be based on the common law of the states or on the Uniform Commercial Code (UCC). Article 2 of the UCC deals with the sales of goods and it has been adopted by most states. The most important products liability sections are the implied and express warranties of merchantability in the sales of goods.

In order to prevail on a product liability claim, the product complained of must be shown to be defective. There are three types of product defects that incur liability in manufacturers and suppliers: design defects, manufacturing defects, and defects in marketing. Design defects are inherent; they exist before the product is manufactured. While the item might serve its intended use, it can be unreasonably dangerous to use due to a design flaw. Manufacturing defects occur during the construction or production of the item. Only a few out of many products of the same type are flawed in this case. Defects in marketing deal with improper instructions and failures to warn consumers of latent or hidden dangers in the product.