A mass tort is a civil lawsuit that involves hundreds or thousands of plaintiffs and one or a few defendants in which the plaintiffs have the same or similar claims against the defendant or defendants. Mass tort lawsuits are often filed as class action lawsuits (a procedural mechanism for joining the plaintiffs in one lawsuit), and are typically based on alleged wrongful acts (torts) such as exposure of the plaintiffs to harmful substances (asbestos or benzene), or defective products (pharmaceuticals or medical devices), or invasions of privacy (data breaches).

In Kansas, as in other states, a mass tort is a type of civil action involving numerous plaintiffs against one or a few defendants where the claims are similar in nature. These cases often arise from exposure to harmful substances, defective products, or privacy violations such as data breaches. Mass torts in Kansas can be filed as class action lawsuits if they meet certain criteria, such as commonality, adequacy, typicality, and numerosity, which are required to certify a class under Kansas law and Federal Rule of Civil Procedure 23. The purpose of a mass tort is to streamline the legal process by consolidating individual claims into a single action, which can be more efficient for the court system and beneficial for plaintiffs seeking relief. However, each plaintiff's damages are typically assessed individually. Kansas courts follow both state statutes and federal laws governing these types of lawsuits, and the specific procedures and requirements will depend on the nature of the tort and the court in which the case is filed.