A mass tort lawsuit is a type of civil legal action in which a large number of plaintiffs file claims against one or more common defendants for harm caused by the same product, action, or event. Unlike a class action—where plaintiffs are treated as a single group with one representative case—mass tort cases involve individual lawsuits that are grouped together because they share similar factual and legal issues. This allows the courts to streamline pretrial proceedings, such as evidence gathering and expert testimony, while still preserving the unique aspects of each plaintiff’s injury and claim.