This is general information, not legal advice, and reflects Ontario law as of September 3, 2026.
What Ontario court rules actually require
Ontario's answer is a certification duty, not a disclosure duty. Since O. Reg. 384/24 took effect, Rule 4.06.1(2.1) requires every factum to carry a signed statement that the lawyer is satisfied as to the authenticity of every cited authority — a rule written because AI tools invent case law that looks real. Authorities on CanLII, a government website, or a court website are presumed authentic; anything else must be checked by a person first. Superior Court of Justice practice directions for civil, family, and criminal proceedings — confirmed together in a February 2026 court news release, though the civil and family AI provisions were already in place before that — reinforce the same idea: whoever files the material must verify every authority, AI-assisted or not. None of that requires saying “AI was used here.” It requires standing behind the result as if written by hand.
Where disclosure actually is mandatory
A few Ontario tribunals go further and require an actual declaration. Under a practice direction dated January 29, 2026, the Ontario Land Tribunal will require the first paragraph of any filing containing AI-generated content to name that content and the person who reviewed it, for hearings starting March 30, 2026 onward. The Information and Privacy Commissioner of Ontario has required something similar since September 2024: parties must state that AI was used, which tool, and confirm the output was reviewed. The Superior Court of Justice, where most Ontario litigation happens, has no equivalent declaration rule today.
What the Law Society Tribunal actually punished
The Law Society of Ontario's April 2024 white paper on generative AI is explicit that it “does not create a requirement that the use of generative AI be disclosed in every instance.” Client disclosure is left to judgment, not a fixed rule. Lee's case shows what happens when that judgment fails twice over. The tribunal found nothing inherently wrong with her using ChatGPT to help prepare an estate factum before Justice Fred Myers; it was explicit that using AI to help prepare court submissions is “not, per se, professional misconduct.” What ended her practice for six months was denying it to the judge, then to the Law Society, before admitting months later that she had written the factum herself and never checked the citations it invented.
The practical rule for now: verify every citation the way Rule 4.06.1(2.1) already requires, and answer honestly if a court or opposing counsel asks whether AI touched the file — certification and candour carry the real weight here, disclosure rules or not. See our explainer on whether AI can give legal advice in Ontario, and our four-question vendor safety checklist. DROZlegal's litigation-drafting tools hyperlink every cited authority to its live CanLII record as a draft is generated — useful for a certification, not a substitute for reading what it cites.
Update, September 4, 2026. A related but separate attestation now applies to Legal Aid Ontario roster lawyers specifically: starting January 2026, LAO's annual Lawyer Self-Report requires them to confirm they've read and comply with the LSO's generative-AI guidance, distinct from the court-filing certification duty above. See our explainer on what the 2026 LAO Self-Report rule actually requires.
Update, September 5, 2026. The practice directions mentioned above aren't just a restatement of Rule 4.06.1(2.1) — they hand the court its own enforcement toolkit on top of the regulation's certification duty. Per the AI-use sections of the Consolidated Civil, Family, and Criminal Provincial Practice Directions (ontariocourts.ca), a judge who finds an uncertified or fabricated authority in a filing can respond with a public reprimand, a costs order, adjourning or dismissing the matter, a contempt proceeding, or a referral to the Law Society of Ontario — on top of, not instead of, the signed certification Rule 4.06.1(2.1) already requires. The regulation sets the duty; the courts' own rules now supply the consequence for breaking it. For a running list of every Ontario court and tribunal AI rule and its effective date, see our Ontario courts AI disclosure rules tracker.
Update, September 14, 2026. The OLT declaration duty described above does not extend to Ontario's highest-volume tribunal caseload. The Landlord and Tenant Board and the Human Rights Tribunal of Ontario answer to a separate body, Tribunals Ontario, not the Ontario Land Tribunal — and Tribunals Ontario's own AI practice direction sets no declaration or certification requirement at all, only advisory guidance to verify AI output and stay personally accountable for accuracy. See our full breakdown of whether the LTB and HRTO require AI disclosure in Ontario.
Update, September 16, 2026. The certification duty described above isn't unique to trial-level filings. Ontario Regulation 275/26 (effective September 1, 2026) also touched the Court of Appeal for Ontario's own factum rules — even though the Court of Appeal has issued no dedicated AI practice direction of its own, unlike the Superior Court's staged civil/family/criminal directions. See our answer on whether the Court of Appeal for Ontario requires AI disclosure.