Non-Party in a Lawsuit: Rights, Subpoenas, and Becoming a Party

A non-party in a lawsuit is any person, business, or organization that hasn’t been named as a plaintiff or defendant but may still be pulled into the case because they hold evidence, records, or knowledge one side needs. You aren’t bound by the judgment and have no stake in who wins, but if you receive a subpoena you have real obligations — and real protections you can use.

What Separates a Non-Party from a Party

The line is drawn by the pleadings. Plaintiffs and defendants are named in the formal filings and are subject to the court’s full authority: they answer discovery, show up when told, and live with the outcome. Non-parties sit outside that framework. Federal rules limit tools like interrogatories and requests for admission to parties only, so a non-party cannot be served with those at all.¹

Non-parties show up in litigation in every imaginable role. An eyewitness to a crash. A bank holding financial records. A former employer with personnel files. A doctor who treated an injury. None of these people chose to be involved, and the law treats their participation differently because of that.

The Subpoena: How Non-Parties Get Pulled In

The subpoena is the bridge between the lawsuit and the outside world. Under Federal Rule of Civil Procedure 45, an attorney authorized to practice in the issuing court can sign and issue a subpoena without a judge’s approval. The clerk of court can also issue one.² That surprises many recipients. A subpoena arriving at your door doesn’t mean a judge personally reviewed your situation; one side’s attorney generated it. The document still carries legal force once properly served, but no judge has necessarily weighed whether the request is reasonable.

Non-party subpoenas come in two forms:

A testimony subpoena (ad testificandum) requires you to appear at a specific time and place to answer questions under oath, usually at a deposition or at trial.
A document subpoena (duces tecum) requires you to hand over specified records, physical items, or electronic data relevant to the case.

A single subpoena can demand both at once.² What’s requested must be identified with reasonable specificity; a subpoena cannot just demand “all your records.”

Your Rights and Protections as a Non-Party

The rules recognize that you didn’t choose to be involved in someone else’s dispute, and they build in several layers of protection. Knowing them changes your position considerably.

Geographic Limits

A subpoena can only compel you to travel within 100 miles of where you live, work, or regularly do business.² If you live in Miami, you cannot be forced to sit for a deposition in New York. The requesting side has to arrange the deposition closer to you or find another way.

One narrow exception applies to trial attendance. If you live in the state where the trial is happening and wouldn’t face substantial expense to attend, the court can compel your appearance even beyond 100 miles.² Parties and their officers face broader geographic obligations and can be compelled to appear anywhere within the state.

Witness Fees

Subpoenaed witnesses in federal court are entitled to a $40 daily attendance fee for each day they’re required to appear, plus mileage reimbursement and parking expenses.³ State courts set their own fee schedules, often lower. The amounts are modest and acknowledge the burden rather than fully compensate for your time.

Objecting to a Subpoena

If you receive a document subpoena, you can push back by serving written objections on the attorney who issued it. The deadline is tight: objections must arrive before the compliance date or within 14 days of service, whichever comes first.² Valid grounds include that the request is overly broad, seeks irrelevant material, or demands information protected by privilege such as attorney-client communications or trade secrets.

If you withhold documents on privilege grounds, you can’t simply stay silent about what you’re holding back. The rules require you to identify withheld materials with enough detail for the other side to evaluate the claim: the general nature of each document, who wrote it, when it was created, and why it qualifies for protection.⁴ This is commonly called a privilege log. Skipping it can cost you the privilege entirely.

Motion to Quash

When objections don’t resolve the dispute, you can ask the court to step in by filing a motion to quash or modify the subpoena. The court must throw out or narrow a subpoena that doesn’t allow reasonable time to comply, exceeds the geographic limits, demands privileged material, or imposes an undue burden.²

This is where a judge weighs the litigants’ need for the evidence against the cost and disruption to you. A court might cut down the volume of documents requested, shift the deposition to a more convenient location, or limit the topics a witness has to address. Concrete hardship persuades judges; vague inconvenience usually doesn’t.

Cost Shifting

You shouldn’t have to foot the bill for someone else’s lawsuit. When compliance requires significant effort, such as sorting through years of records or engaging IT staff to extract archived data, the court must protect you from bearing that expense.² The requesting side may be ordered to cover the reasonable costs of compliance, including copying, retrieval, and review.

Cost shifting isn’t automatic. You need to show that compliance involves real expense, and the court decides what counts as reasonable. But the principle is on your side: the financial burden of producing evidence should fall on the people who need it for their case, not on bystanders.

What Happens If You Ignore a Subpoena

A subpoena is not a suggestion, and this is where non-parties most often get themselves into trouble. Under Rule 45(g), a court may hold in contempt any person who fails to obey a properly served subpoena without an adequate excuse.² Contempt can mean fines, an order to pay the other side’s attorney’s fees and lost earnings, or in extreme cases jail until you comply.

Enforcement cuts both ways. The court can also sanction the attorney who issued the subpoena if they failed to take reasonable steps to avoid burdening you.² An attorney who fires off an unreasonably broad subpoena and ignores your objections can face financial penalties from the same judge.

The practical takeaway: respond. Even if you disagree with what’s being asked, file objections or a motion to quash within the deadline. Sitting on a subpoena and hoping it goes away is the worst available option.

When a Non-Party Becomes a Party

The line between party and non-party isn’t always permanent. Federal rules provide several paths by which a non-party can end up formally in the case, either by choice or by force.

Intervention

If you believe a lawsuit’s outcome could directly harm your interests, you can ask the court for permission to join it. Rule 24 recognizes two types. Intervention of right is mandatory: the court must allow it when you have an interest in the property or subject matter at stake, the case’s resolution could impair your ability to protect that interest, and the existing parties don’t adequately represent it.⁵ A co-owner of disputed property who wasn’t named in the original suit is a classic example.

Permissive intervention is discretionary. The court may allow you to join if your claim or defense shares a common question of law or fact with the main case, provided intervention won’t cause undue delay or prejudice.⁵ Either way, the motion must be timely and accompanied by a pleading laying out what you intend to argue.

Impleader

A defendant who believes a non-party is actually responsible for what the plaintiff is claiming can pull that non-party into the case. Under Rule 14, the defendant files a third-party complaint arguing, in essence, that if they owe the plaintiff anything, the non-party owes them.⁶ You then become a third-party defendant with full party obligations: you must answer, participate in discovery, and can be held liable in the judgment. This is common in construction disputes and insurance cases, where liability cascades through multiple parties.

Required Joinder

Sometimes a court concludes that a fair resolution is impossible without a specific non-party. Rule 19 requires joinder when the court can’t grant complete relief among the existing parties without the absent person, or when proceeding without them would impair that person’s interests or expose an existing party to conflicting obligations.⁷

If you can be served and adding you won’t destroy the court’s jurisdiction, the court orders you joined. A non-party who refuses to join as a plaintiff can be made a defendant instead. If joinder isn’t feasible, for instance because adding you would eliminate diversity jurisdiction, the court must decide whether the case can fairly proceed at all or should be dismissed.⁷

1
Legal Information Institute. Federal Rules of Civil Procedure Rule 33 – Interrogatories to Parties
2
Legal Information Institute. Federal Rules of Civil Procedure Rule 45 – Subpoena
3
Office of the Law Revision Counsel. 28 USC 1821 – Per Diem and Mileage Generally
4
Legal Information Institute. Federal Rules of Civil Procedure Rule 26 – Duty to Disclose; General Provisions Governing Discovery
5
Legal Information Institute. Federal Rules of Civil Procedure Rule 24 – Intervention
6
Legal Information Institute. Federal Rules of Civil Procedure Rule 14 – Third-Party Practice
7
Legal Information Institute. Federal Rules of Civil Procedure Rule 19 – Required Joinder of Parties