Two different appointments
Ontario has two related but distinct offices. A Commissioner for Taking Affidavits administers oaths, affirmations and declarations for documents used within Ontario. A Notary Public has all of those powers and more: a notary can also witness signatures, certify true copies of documents, and issue notarial certificates, including for documents that will be used outside Ontario or outside Canada.
When a commissioner is enough
If your document is an affidavit or statutory declaration that will be filed with an Ontario court, tribunal, municipality, school or other Ontario body, a commissioner is usually all you need. Court affidavits, OSAP declarations, insurance declarations and municipal forms fall in this group.
When you need a notary
Choose a notary when the document is going outside Ontario or outside Canada, when you need a certified true copy of an original, or when the receiving party specifically asks for notarization or a notarial seal. Foreign pension forms, immigration support documents, international business papers and anything headed for authentication or an apostille all call for a notary.
Lawyers are automatically both
Every practising Ontario lawyer is automatically a commissioner and is entitled to act as a notary public. Non-lawyer commissioners, by contrast, often have limited appointments — some can only commission specific documents for a specific employer. If a non-lawyer commissioned your document, check that their appointment covers it.
If you're not sure
Tell us what the document is and where it's going. The safest default for anything leaving the province is a notary — a notarization is accepted anywhere a commissioned document would be, but not the other way around.
General information only — not legal advice. Requirements depend on your document and the institution receiving it; we confirm what applies before you book.