In the legal world, various officials are authorized to administer oaths and witness signatures to lend authenticity to important documents. Two of the most common roles encountered in Ontario are the Commissioner for Taking Affidavits (often called a Commissioner of Oaths) and the Notary Public.

While these terms are frequently—and incorrectly—used interchangeably, they possess distinct powers under Ontario law. Knowing the difference can save you significant time and ensure your legal documents are properly executed for their intended purpose, especially when dealing with international matters.

Who is a Commissioner for Taking Affidavits (Commissioner of Oaths)?

A Commissioner for Taking Affidavits is an individual authorized under the provincial Commissioners for Taking Affidavits Act to administer an oath or a solemn affirmation for affidavits and statutory declarations.

Primary Role: Commissioning

The core function of a Commissioner is to confirm that the person (the deponent or declarant) appearing before them has:

Presented valid government-issued photo identification to verify their identity.
Read and understand the contents of the document.
Sworn (taken an oath) or affirmed (made a solemn declaration) that the facts contained within the document are true and correct to the best of their knowledge.
Signed the document in the Commissioner’s presence.

The Commissioner’s signature and printed name on the document certify the proper administration of the oath or affirmation, but they do not verify the truthfulness of the document’s content itself. That responsibility rests solely with the person signing.

Authority in Ontario

By Virtue of Office: All licensed lawyers and paralegals in good standing with the Law Society of Ontario (LSO) are automatically Commissioners for Taking Affidavits.
By Appointment: Other individuals, such as certain government employees, court clerks, or those working in a specific business context that regularly requires commissioning (e.g., a law firm or an insurance company), can apply to the Attorney General of Ontario for an appointment.

Who is a Notary Public?

A Notary Public in Ontario is an official appointed under the Notaries Act. Crucially, a Notary Public holds all the powers of a Commissioner for Taking Affidavits and possesses additional, expanded authority.

Expanded Authority: Notarizing and Certifying

The unique powers of a Notary Public include:

Commissioning Documents: Administering oaths and solemn affirmations for affidavits and statutory declarations (the same as a Commissioner).
Certifying True Copies: Certifying a photocopy of an original document (such as a passport, birth certificate, or diploma) as a “certified true copy.” This process involves the Notary Public comparing the copy to the original and declaring, under their seal, that the copy is a true, accurate, and unaltered reproduction.
Attesting Execution: Witnessing or attesting the execution (signing) of a document, particularly those for international use.

Authority and the Notary Seal

The Notary’s broader authority, particularly for certifying true copies, is essential for documents that will be used:

Outside of Ontario (interprovincially or internationally).
For immigration purposes.
By foreign governments or educational institutions.

When a Notary Public signs a document, they must also affix their official Notary Seal (often an embossed or rubber stamp). The seal, along with their signature, is what gives the document its international recognition, as it can often be further verified through an authentication or apostille process if required by a foreign jurisdiction.

Understanding the Key Difference

The most significant distinction is the ability to certify true copies and the implicit international recognition conferred by the Notary Seal.

Feature	Commissioner for Taking Affidavits (Commissioner of Oaths)	Notary Public

Certifying Copies	Cannot certify documents as true copies of the original.	Can certify documents as true copies of the original.
Scope of Use	Primarily for use within the Province of Ontario.	For use within Ontario, interprovincially, and internationally.
Seal Required	Uses a stamp with name/designation. No official seal required.	Must affix an official Notary Seal (essential for international acceptance).
Legal Professionals	All LSO licensed lawyers and paralegals are Commissioners by virtue of office (automatic).	LSO licensed lawyers and paralegals must apply and pay a fee to be appointed a Notary Public (not automatic).

Summary: Why Choose One Over the Other?

If you simply need to swear an oath to the truthfulness of an Affidavit or Statutory Declaration for a local matter (e.g., a court form or a specific government document), a Commissioner of Oaths is sufficient.

If you need a certified true copy of a document, or if your document is headed for use outside of Canada or another province (e.g., a travel consent letter, a foreign visa application, or verifying a degree), you absolutely require a Notary Public.

FAQ

Where can I get my affidavit commissioned?

You have two convenient options through The Notary Guy. You can visit one of our in-person locations in the Greater Toronto Area and Hamilton, including Mississauga, Brampton, Stoney Creek, Hamilton, Scarborough, and Etobicoke. Alternatively, for maximum flexibility, we offer a hassle-free online remote commissioning service as well.