Duhaime's Law Dictionary

Third Party Claim Definition:

A claim made by a defendant within existing legal proceedings seeking to enjoin a person not party to the original action, to enforce a related duty.

Related Terms: Third Party

Also referred to as third party proceedings.

A formal claim and proceeding taken, usually by some defendant, to draw a third party into existing litigation.

In Metz, the Alberta Court of Appeal wrote of the notice of filing a third party claim as follows:

"Third party notices serve to enforce duties which the third party owes to the defendant issuing the third party notice."

The classic example is when a defendant claims indemnity from a third party or, as Justice Johnstone wrote in Escobar:

"In some circumstances, third party proceedings are conducted with a view to determining the apportionment of negligence between or among defendant(s) and a third party or third parties."

Other than the litigation benefit to the defendant who draws in a third party by way of a third party claim, the final disposition has the potential of forming res judicata as between the defendant and the third party.

As it is not uncommon for a defendant to seek to draw another person into litigation to share the risk, most jurisdictions have rules which delineate the limits of third party claims. This codification is taken from the 2009 version of Rule 22(1),  Supreme Court Rules of British Columbia:

"A party of record who is not a plaintiff may file a third party notice ... if the party of record alleges against any ... third party whether or not the third party is a party to the action, that the party is entitled to contribution or indemnity from the third party in respect of a claim made against the party in the action, the party is entitled to any relief against the third party relating to or connected with the original subject matter of the action, or a question or issue relating to or connected with any relief claimed in the action or with the original subject matter of the action is substantially the same as a question or issue between the party and the third party and should properly be determined in the action."

In the United States Federal Practice Rules:

"A defending party may, as third-party plaintiff, serve a summons and complaint on a nonparty who is or may be liable to it for all or part of the claim against it."

In the Conduct of Civil Litigation, authors Fraser and others write:

"A third party proceeding is an assertion of a cause of action by the defendant (against a third party) which may exist independently of or may be dependent upon the existence of a cause of action between the plaintiff and the defendant."


  • Duhaime, Lloyd, Legal Definition of Third Party
  • Escobar v Yacey, 229 AR 278 (ABQB 1998)
  • Fraser, P. and others, "Third Party Procedure", The Conduct of Civil Litigation in British Columbia, Chapter 39, (Toronto: LexisNexis, 2007), page 39-1.
  • Metz v Breland, 76 Alta. LR 2d 397 (1991, ABCA)
  • Saskatchewan Co-operative Elevator Co. v. Grand Trunk Pacific Railway, 1 DLR 532 (1923)
  • Stevenson, W. and Cote, J., "Third Party Claims", in Civil Procedure Encyclopedia, Chapter 19 (Edmonton: Juriliber, 2003)
  • Supreme Court Rules, B.C. Reg. 221/90

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