Rule 37.Additional Parties

Last verified June 28, 2026

In one sentenceRule 37 lets either side bring necessary or proper additional parties into a suit before trial, on terms the court sets, so long as it does not unreasonably delay the trial.

Full Text of Rule 37

Text size

Before a case is called for trial, additional parties necessary or proper parties to the suit, may be brought in, either by the plaintiff or the defendant, upon such terms as the court may prescribe; but not at a time nor in a manner to unreasonably delay the trial of the case.

End

Plain-English Summary

Rule 37 is the general rule for adding parties. Before a case is called for trial, either the plaintiff or the defendant may bring in additional parties who are necessary or proper to the suit, on whatever terms the court prescribes.

The timing has a guardrail. Parties cannot be added so late, or in a way, that unreasonably delays the trial.

Frequently Asked Questions

When can you add a party to a Texas suit?

Before the case is called for trial, under Rule 37, on the court's terms — but not at a time or in a manner that unreasonably delays the trial.

Can either side add parties under Rule 37, or just the plaintiff?

Either side. Rule 37 lets the plaintiff or the defendant bring in additional parties who are necessary or proper to the suit.

Does the court set conditions on adding a party?

Yes. Rule 37 lets the court prescribe the terms for bringing in an additional party, giving it room to protect the other parties while the lineup changes.

Source & verification. Rule text and the official Notes and Comments are reproduced verbatim from the Texas Rules of Civil Procedure (Tex. R. Civ. P. 37), published by the Texas Judicial Branch (txcourts.gov). Promulgated by the Supreme Court of Texas. The plain-English summary is original and draws on official sources. Last verified June 28, 2026. · Official source

Also known as: additional partiesadding partiesnecessary partiesproper partiesTRCP 37