A real party in interest is the person or entity whose rights are involved and stands to gain from a lawsuit or petition even though the plaintiff who filed suit is someone else, often called a "nominal" plaintiff. It is the person who will be entitled to benefits of a court action if successful; one who is actually and substantially interested in the subject matter, as opposed to one who has only a nominal, formal, or technical interest in or connection with it. It may be broadly defined as someone who may be adversely affected by the relief sought or the person or entity entitled to the benefits if the action is successful.
Under the Federal Rules of Civil Procedure (FRCP), FRCP 17(a) provides that "every action shall be prosecuted in the name of the real party in interest", so that the named plaintiff must have, under the governing substantive law, the right sought to be enforced. The real party in interest is not necessarily the person who ultimately will benefit from the successful prosecution of the action.
The following is an example of a state statute involving real parties interest:
(a) "Except as otherwise provided in clauses (b), (c) and (d) of this rule, all actions shall be prosecuted by and in the name of the real party in interest, without distinction between contracts under seal and parol contracts.
(b) A plaintiff may sue in his own name without joining as plaintiff or use-plaintiff any person beneficially interested when such plaintiff
(c) Clause (a) of this rule shall not apply to actions where a statute or ordinance provides otherwise."
