Guides · reviewed 2026-09-04

How to name the right defendant

Legal information, not legal advice. Results depend on the facts of your case.

Legal information, not legal advice. This guide and our free tools give legal information. They do not give advice about your case. A licensed lawyer can give legal advice.

The answer

Your claim must state the full name of each party and, if relevant, the capacity in which they are sued. A judgment against the wrong name can be hard to enforce. Get the name right before you file.

Find the legal entity

  • A corporation: use the exact legal name, with "Inc.", "Ltd.", or "Corp.". A store name is often a registered business name, not the legal name.
  • A numbered company: sue the number name, for example "1234567 Ontario Inc.", and add the business name it uses.
  • A sole proprietorship: the business is a person. Sue the person, and add the registered business name.
  • A partnership: you can sue the partners in the firm name.
  • Search the Ontario Business Registry to confirm the name and the status.

Your own name matters too

A person or a business that uses an unregistered business name cannot keep a court case about that business. It needs leave of the court. The court grants leave when the failure to register was inadvertent, nobody was misled, and the name is registered by the time you ask. Register the name, or sue in your own legal name.

More than one defendant

You can name more than one defendant in one claim. Extra parties go on Form 1A, attached after the first page. If 2 parties had a role in your loss, you can name both. You can file where any one of them lives or does business. Serve each defendant separately and file a Form 8A for each.

A defendant under 18

A defendant under 18 defends through a litigation guardian, and service must reach both the minor and the parent or custodian.

What to do

  1. Collect every name you have: the contract name, the invoice name, the e-transfer name, and the sign name.
  2. Search the Ontario Business Registry for each name.
  3. Check who you paid: the person, or the company.
  4. Write the full legal name on Form 7A, and add the business name it uses: /build/7a.
  5. Not sure between a person and their company? Get legal advice before you file.

To fix a wrong name

You can amend the claim. Mark it "Amended", underline the additions, attach the documents again, and serve it on every party, including a party in default. File and serve the amended claim at least 30 days before the trial date, unless the court allows less time or the parties consent. A person added as a party must be served with the amended claim. The 2-year limitation period can bar a claim against a new party. Get advice before you add one after the date.

Common mistakes

  • The name on the truck or the sign is often not the legal name.
  • One person can run several companies. Sue the one your contract names.
  • A dissolved corporation can pay you nothing. Check the status in the registry.
  • Do not guess the spelling. Copy the registry entry exactly.

When to get a lawyer

Get legal advice if the correct defendant is not clear, or several parties had a role. Legal services provided by Mithril Law — Jonathan Kleiman, licensed Ontario lawyer.

Free tools