How to Sue for an Unpaid Invoice in Ontario Small Claims Court
Check the Basics Before You File
Ontario Small Claims Court handles claims up to $50,000 (exclusive of interest and costs), which covers the vast majority of unpaid invoice disputes between businesses, freelancers, and individuals. Before you file, confirm two things.
First, the Limitations Act, 2002 generally gives you two years from when you discovered (or should have discovered) the debt to start a court proceeding. For a liquidated debt, a clear and unequivocal written acknowledgment of liability, signed by the debtor or their agent, or a partial payment can restart the period only if made before the original period expires. A later acknowledgment does not revive an expired claim. Because the discovery date can be fact-specific, get legal advice if the date is close or uncertain.
Second, verify the debtor's exact legal name. If they are a sole proprietor, you sue the individual "carrying on business as [trade name]." If they are incorporated, run a search through the Ontario Business Registry to get the precise corporate name. A judgment against a trade name alone can be unenforceable when you try to garnish a bank account or register a writ.
Send a Demand Letter First
A formal demand letter is not legally required, but it records when you requested payment, demonstrates reasonable conduct, and sometimes gets you paid without ever filing. Under section 128 of the Courts of Justice Act, statutory pre-judgment interest generally runs from when the cause of action arose; a demand date matters if the agreement makes payment due on demand.
Keep the letter factual. State the amount owed, reference the invoice numbers and dates, give a payment deadline of 10 to 14 calendar days, and include your payment details. Send it by registered mail or courier so you have a delivery receipt. Do not threaten anything you would not actually do, and do not use language that could be read as harassment.
File Your Claim
Complete the Plaintiff's Claim (Form 7A). Your statement of claim should be in plain language — no legal jargon needed — and should cover what the agreement was, what work or goods you delivered, the invoiced amount, and the fact that the debtor has not paid despite your demand.
Attach copies of your contract or written agreement, the unpaid invoices, proof of delivery or completion, and a copy of your demand letter with the delivery receipt. Rule 7.01(2) requires you to attach any written document your claim is based on.
File at the courthouse in the territorial division where the debtor resides or carries on business, or where the work was performed. The filing fee is $108 for infrequent claimants.
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Serve and Wait for a Response
Serve the issued claim on the debtor within six months. For a corporation, you can use registered mail to their registered office address. For an individual, personal service — handing them the documents directly — is the most reliable method.
The debtor has 20 days after service to file a Defence (Form 9A). If they do not file within 20 days, file your Affidavit of Service (Form 8A) and Request to Clerk (Form 9B) to have them noted in default. For a liquidated debt — a fixed sum like an unpaid invoice — you can then request judgment on Form 11B; the clerk signs it without a hearing. That is often the fastest path to a judgment on an unpaid invoice.
If the debtor does file a defence, the clerk schedules a mandatory settlement conference before a deputy judge. Come prepared with an organized evidence binder: invoices, the contract, delivery records, email correspondence, and your interest calculation.
Get the Full Roadmap
Our Ontario Small Claims Court filing guide covers every step in detail — from verifying the debtor's legal name through enforcement options like garnishment and writs of seizure and sale. It includes a pre-judgment interest calculator, a service tracker, and worked examples for completing Form 7A.
Get Your Free Ontario Small Claims Filing Checklist
Download the Ontario Small Claims Filing Checklist — a printable guide with checklists, scripts, and action plans you can start using today.