If you filed the lawsuit, you are the plaintiff. If you were served with a complaint and summons, you are the defendant. That is the short answer to whether you are the plaintiff or defendant in a lawsuit, and the rest of what matters flows from it: the plaintiff started the case and has to prove it, and the defendant has to respond on a tight clock or risk losing without a fight.
The roles look symmetrical from the outside. They are not. Each side has different deadlines, different burdens, and different leverage.
How to Tell Which Side You Are On
Look at the caption of the court papers. The party listed first, before the “v.,” is the plaintiff. The party listed after is the defendant. If your name appears first, you filed. If your name appears second and someone handed you a summons and a complaint, you were sued.
In a civil case, the plaintiff is the person or entity claiming harm and asking the court for a remedy. The defendant is the person or entity accused of causing that harm. Straightforward cases have one of each. More complicated ones name multiple defendants, and sometimes multiple plaintiffs, but the basic split holds.
What It Means to Be the Plaintiff
As the plaintiff, you control the opening moves. You choose when to file, which court to file in, and how to frame the claims. That initiative comes with real obligations before a court will hear you out.
You Need Standing and the Right Court
Standing means you personally have a stake in the dispute. Courts do not let people sue over injuries that happened to someone else or over abstract grievances. A contract claim, for instance, can only be brought by someone who was a party to the agreement or was directly harmed by its breach.
Jurisdiction is the second gate. Subject matter jurisdiction asks whether the court handles this type of case at all. Federal courts hear cases involving federal law, constitutional questions, or disputes between residents of different states. Personal jurisdiction asks whether the court has authority over the defendant, usually because the defendant lives, works, or does business in the court’s geographic area. File in the wrong court and the case gets dismissed before it starts.
You File a Complaint
The complaint is the document that starts the case. It has to identify the legal basis for the court’s authority, describe what happened, explain why the defendant is legally responsible, and specify what you want the court to do. A vague or incomplete complaint invites a motion to dismiss, which is the defendant’s way of asking the court to throw the case out at the door.
You Carry the Burden of Proof
In a civil case, the plaintiff has to prove the claim by a “preponderance of the evidence.” That means showing your version is more likely true than not — tipping the scales just past 50-50. It is a lower bar than the “beyond a reasonable doubt” standard used in criminal trials, which is why the same conduct can lose a civil case and still result in a criminal acquittal.
You Have a Filing Deadline You Cannot Miss
Every type of claim has a statute of limitations. Miss it and the claim is dead, no matter how strong the evidence. Deadlines vary by claim type and jurisdiction. Personal injury claims typically allow one to six years depending on the state. Contract disputes often run longer. For federal claims created by laws passed after December 1, 1990, the default is four years from when the cause of action arose, unless the specific statute says otherwise.1Office of the Law Revision Counsel. 28 USC 1658 – Time Limitations on the Commencement of Civil Actions Arising Under Acts of Congress
What It Means to Be the Defendant
As the defendant, you did not choose to be in court. Your first job is to respond, and the clock starts the moment you are served.
You Have to Be Formally Served
Before you owe the court anything, the plaintiff has to deliver the complaint and a summons to you through a process called service of process. The rule exists so that no one faces a lawsuit they do not know about. Federal courts require service within 90 days of filing or the case risks dismissal. Corporations are typically served through a registered agent — a person the company has designated to receive legal documents on its behalf.
You Have a Short Window to Answer
In federal court, the defendant generally has 21 days after being served to file an answer. If you agreed to waive formal service, the window extends to 60 days, or 90 days if you are outside the United States. If you file a motion to dismiss instead and the court denies it, you get 14 more days to file the answer.2Legal Information Institute. Federal Rules of Civil Procedure Rule 12 – Defenses and Objections State court deadlines are often 20 to 30 days.
The answer is where you admit or deny each of the plaintiff’s claims and raise any defenses. It is not optional.
Ignoring the Lawsuit Loses It
If you fail to answer or file any response, the plaintiff can ask the court clerk to enter a default. Once default is on the record, the plaintiff can seek a default judgment, which effectively means winning without a trial because you never showed up. When the amount owed can be calculated with certainty, the clerk can enter the judgment without a hearing. In other cases the judge does it, sometimes after a hearing on damages. Courts can set aside a default judgment for good cause, but undoing one is far harder than answering on time.3Office of the Law Revision Counsel. Federal Rules of Civil Procedure Rule 55 – Default
You Do Not Have to Prove Anything — Usually
The plaintiff carries the burden of proof, so as a defendant you can win by showing the evidence does not add up. The plaintiff has to build something. You only have to knock it down.
The exception is an affirmative defense, which is an argument that even if everything the plaintiff says is true, you are still not liable for a specific legal reason. Self-defense in an assault case or the expiration of the statute of limitations are common examples. When you raise an affirmative defense, the burden shifts and you have to prove that defense applies.
If You Are Sued but Think Someone Else Is Really at Fault
Being the defendant does not mean you are stuck playing defense. Three tools let you push back.
Counterclaims Against the Plaintiff
A counterclaim is a claim you file against the plaintiff in the same lawsuit. In a breach of contract case, for instance, you might allege the plaintiff breached first. Federal rules divide counterclaims into two categories. A compulsory counterclaim arises out of the same transaction as the plaintiff’s claim and must be raised in the current lawsuit or it is forfeited forever. A permissive counterclaim involves a separate dispute and can be filed here or saved for a later suit.4Legal Information Institute. Federal Rules of Civil Procedure Rule 13 – Counterclaim and Crossclaim
The compulsory rule is where defendants get burned. A related claim you do not raise is gone.
Crossclaims Against a Co-Defendant
If you are one of several defendants and you think another one is the real cause, you can file a crossclaim against that co-defendant. Crossclaims must arise out of the same transaction or occurrence as the original lawsuit.
Bringing in a Third Party
If someone who is not in the lawsuit is really to blame, Federal Rule 14 lets you pull them in through a process called impleader. You can file a third-party complaint within 14 days of serving your original answer without needing court permission. After that, you have to ask the judge for leave.5Legal Information Institute. Federal Rules of Civil Procedure Rule 14 – Third-Party Practice The classic example is a general contractor sued for defective construction who then brings in the subcontractor whose work actually caused the problem. The third-party complaint does not say “I am not liable.” It says “If I am liable, this other party owes me reimbursement.”
Being on the Same Side as Other Defendants
Lawsuits often name more than one defendant. A product liability case might target the manufacturer, the distributor, and the retailer. A car accident case might name both the driver and the municipality that maintained a poorly designed intersection.
When multiple defendants share responsibility, a principle called joint and several liability can apply. That means the plaintiff can collect the full judgment from any one of them. If Defendant A and Defendant B are both found liable for $200,000, the plaintiff does not have to collect $100,000 from each. The plaintiff can go after whichever defendant has deeper pockets for the whole amount. That is a hard reality to plan for if you are the co-defendant with the assets.
What Both Sides Have to Share
Once the pleadings are filed, both parties enter discovery. Under federal rules, four categories of information have to be handed over automatically, without anyone asking:
- Names, addresses, and phone numbers of anyone likely to have relevant information, along with a description of what they know
- Copies or descriptions of all documents and electronically stored information a party may use to support its claims or defenses
- A breakdown of every category of damages being claimed, backed by the documents used to reach those numbers
- Any insurance policy that might cover part or all of a judgment
Hiding relevant information risks sanctions, and evidence withheld during discovery can be excluded at trial.6Legal Information Institute. Federal Rules of Civil Procedure Rule 26 – Duty to Disclose Beyond initial disclosures, discovery includes depositions, written interrogatories, and requests for documents. It is usually the longest and most expensive phase of the case, and it is where most cases settle, because once both sides see the evidence, the likely outcome at trial comes into focus.
What Each Side Pays
Filing a civil case in federal court costs $405 to start, made up of a $350 statutory fee and a $55 administrative fee. State court fees vary by court type and by the amount in dispute. Plaintiffs who genuinely cannot afford the fee can apply to proceed in forma pauperis by submitting an affidavit of financial hardship. The court can waive fees entirely but will dismiss the case if it finds the claim frivolous or legally insufficient.7Office of the Law Revision Counsel. 28 USC 1915 – Proceedings in Forma Pauperis
Under the American Rule, each side pays its own attorney fees regardless of who wins. This is the default in most civil cases. Some federal statutes, particularly in civil rights, employment discrimination, and consumer protection, let a prevailing plaintiff recover fees from the defendant. Contracts sometimes include fee-shifting provisions. But unless a statute or contract says otherwise, winning does not mean the other side pays your lawyer.
Both sides face financial risk from filing papers that are frivolous or filed for an improper purpose. Federal Rule 11 lets courts sanction attorneys or parties for such filings, including by ordering them to pay the other side’s reasonable attorney fees caused by the violation. A safety valve gives the offending party 21 days to withdraw or correct the filing before sanctions can be imposed.8Legal Information Institute. Federal Rules of Civil Procedure Rule 11 – Signing Pleadings, Motions, and Other Papers
How the Roles Play Out in Practice
The plaintiff sets the agenda. They pick the timing, the forum, and the theory of the case. They also front the money and carry the burden. If the evidence they build does not tip the scales past 50-50, they lose.
The defendant reacts. Their job is to attack the plaintiff’s case, challenge evidence, and raise defenses. Because the plaintiff has the burden, a defendant can win by showing the plaintiff’s proof is thin, even without offering an alternative story.
Settlement pressure feels different from each seat. Plaintiffs weigh a guaranteed recovery against the risk of losing at trial and getting nothing. Defendants weigh the cost of settling now against the risk of a larger verdict plus years of additional legal fees. The vast majority of civil cases settle before trial, often during or shortly after discovery, when both sides have seen enough to make a realistic assessment of what a trial would produce.