A crossclaim is a claim by one party to civil litigation against a co-party on the same side of a lawsuit. Crossclaims are differentiated from counterclaims, which are claims by a defendant against the plaintiff who initially brought the action against him or her. Much like a counterclaim, a crossclaim may only be filed if it relates to a matter of the original jurisdiction. Crossclaims are promoted as a matter of policy because they are in the interest of expediency in the judicial economy.
Crossclaims are filed between parties of the same action, on the same side of the action. For example, a defendant may file a crossclaim against another named defendant, and a plaintiff may file against another named plaintiff. They are encouraged in the interest of efficiency, as court systems all over the world are perpetually backlogged with cases; crossclaims help consolidate the various legal battles between parties that arise from the same event. As part of this policy, some jurisdictions require that any party to an action that has a claim against a co-defendant or co-plaintiff must bring that crossclaim during the original action if the claim arises out of the same set of operative facts as the original action. This is called a “compulsory crossclaim” and in those jurisdictions if the party does not file, they will be barred from bringing a separate action once the original case is decided.
The main requirement for one party to be able to file a crossclaim against another is that the claim must be a matter of original jurisdiction with regard to the lawsuit. Original jurisdiction is the right of a court to hear a case for the first time. It is established with regard to the crossclaim as long as the reason for the crossclaim arose out of the same transaction or occurrence that led to the original claim. This relates to the policy of consolidation dictated above. It makes sense to litigate multiple claims arising from the same event at once rather than bringing several separate actions that rehash the same facts from different perspectives.
An example of a typical scenario that would involve a crossclaim is one where there are several vehicles in an accident. One party who was clearly not at fault may bring an action as the plaintiff against two parties who may have each driven negligently to different degrees. If one of the negligent drivers feels the other negligent driver, who is his co-defendant, was at fault for an injury he suffered in the accident then he may file a crossclaim against the other negligent driver for his injuries as well.