necessary party

A necessary party is a person or entity whose legal interests are directly affected by the outcome of a case. In Shields v. Barrow, 58 U.S. 130 (1854), the Supreme Court distinguished necessary parties from indispensable parties. Under Rule 19 of the Federal Rules of Civil Procedure, a necessary party should be joined if feasible. Joinder may be excused when the party’s inclusion would destroy complete diversity, a requirement for a federal court to have subject matter jurisdiction. Another reason would be if court would be an improper venue for the necessary party. In this context, the inability to join a necessary party would not mean the lawsuit would have to be dismissed, as separate actions could be brought by or against them. Indispensable parties, on the other hand, are so integral to the lawsuit that the action cannot proceed without them. Thus, the lawsuit would have to be dismissed if they could not be properly joined.

In state courts, there is not always a distinction between necessary and indispensable parties. In some states, the terms are used interchangeably, and in other states the term “indispensable” is not used at all. 

For detailed analysis, see: Fleming, James, Necessary and Indispensable Parties, 18 U. Miami L. Rev. 68 (1963), available at https://repository.law.miami.edu/umlr/vol18/iss1/11

[Last reviewed in November of 2025 by the Wex Definitions Team] 

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