1. Decide whether you need a claim of your own
A defence asks the court to reject all or part of the plaintiff’s case. A defendant’s claim asks for relief against the plaintiff or another person. You might say the plaintiff also owes you money, or that someone else should reimburse you if you are liable. Each proposed claim needs a factual and legal basis; naming a person simply because they were involved is not enough.
Consider whether the claim is connected to the dispute, within the court’s jurisdiction and within the applicable limitation period. Distinguish a defence of payment or set-off from a request for a separate judgment in your favour. Get advice if you are unsure which remedy to plead.
Official reference: Ontario: replying to a claim
2. Prepare and file Form 10A
Complete the current Defendant’s Claim, Form 10A, using the original action’s file number and court office. Identify each person you are claiming against by legal name and address. State the events, their responsibility and your calculation; attach the records supporting the claim.
The usual deadline is within 20 days after filing your defence, unless the court gives permission to file later. This is a different deadline from the 20-day period for defending the plaintiff’s claim. Do not assume bringing your own claim extends the defence deadline or overrides a limitation period. A filing fee applies.
Official reference: Ontario: making a claim
3. Serve every person who must receive it
Arrange service of the issued defendant’s claim under the claim-service rules, not merely the ordinary methods for later correspondence. A newly added person must receive the required original claim materials as well. Check Rule 10 and the service guide for the complete package.
Record the method, date, time, address and person served. Have the server complete the required affidavit. Generally, an issued claim must be served within six months, subject to a court extension. Track the response deadline separately for each recipient.
Official reference: Official Small Claims Court forms
4. If you receive a defendant’s claim
Being the original plaintiff does not mean you can ignore a claim against you. A person served with a defendant’s claim generally has 20 days after service to serve and file Form 9A in response. Use the same care with admissions, proof of service and acceptance confirmation.
Keep the issues distinct when preparing for settlement or trial: the original claim and the defendant’s claim can have different burdens, losses and outcomes. Make any settlement document clear about whether it resolves both claims and all parties.
Official reference: Rules of the Small Claims Court, O. Reg. 258/98
Your next-step checklist
Use this list as you work. Check marks apply to this visit only.
Sources for this guide
Where to go next
Need help with your next step?
Ask about available assistance, scope and fees. Include any urgent court deadline.
General information for Ontario, not advice about your case. Legislation, court orders and current court directions govern. Get help with your situation.