DEFINITION of 'Plaintiff'

A plaintiff is the party that brings a lawsuit to court. Plaintiffs exist in civil cases, not criminal cases.


In a civil case, the plaintiff is the party that claims injury due to the actions of another party, referred to as the defendant. The plaintiff may be an individual, a business, or a group. In a class action lawsuit, which brings together a large number of individuals claiming injury from the same party, the part names on the lawsuit is referred to as the lead plaintiff or named plaintiff.

The plaintiff initiates a lawsuit by filing a complaint with the court. The complaint document is filed with the clerk, and is often drafted by an attorney. The document outlines the damages or injury that the plaintiff claims, how the defendant was the party that caused the injury, and what remedy the plaintiff is seeking. After the complaint is filed, the court will issue a summons detailing the lawsuit and notifying the defendant that it can issue a response to the lawsuit by a specific date and time. At this point, the plaintiff and defendant may choose to settle outside of court in order to avoid the expenses associated with trying the case.

If the case goes to trial, the plaintiff is responsible for proving that the defendant was the party responsible for causing the injury. Civil cases require the plaintiff to show a preponderance of evidence pointing to the defendant causing injury. This is a different threshold than in criminal cases, in which the plaintiff must show that the defendant is guilty beyond a reasonable doubt. In some instances, the defendant may be found not guilty in a criminal case, but found guilty in a civil case relating to the same or similar occurrence.

If the plaintiff is able to show during a trial that the defendant caused injury, the court will issue a judgment outlining what damages the defendant is responsible for. The type of judgment issued depends on the factors of the case and the actions (or inactions) of the defendant. In a default judgment, a judge can find for the plaintiff because the defendant failed to take action by, for example, not contesting the lawsuit. A summary judgment can be issued if one party in the case wants to avoid a full trial, and is sought when available evidence points to an obvious outcome.

For example, the Securities Exchange Commission (SEC) served as a plaintiff in a complaint against defendants David Blaszczak, Christopher Worrall, Theodore Huber, and Jordan Fogel for engaging in insider trading. Worrall, a federal government employee, tipped his friend Blaszczac by illegally disclosing material non-public information on planned actions of the agency he worked for. Blaszczac, in turn, tipped his friends, Huber and Fogel, who were analysts at an adviser firm. The adviser firm traded in the securities of the companies in which the government agency was making a move on, and netted over $3.9 million from the trades.

The word “plaintiff” is not used to describe the party bringing a criminal case; instead, the word “prosecution” is used. The prosecution in a criminal case is not a private party, but a local, state, or federal government. In some jurisdictions the word “plaintiff” has been replaced by the word “claimant”.