Can someone who lives outside Ontario or Canada be an executor of an Ontario estate?

Yes, in many cases a named executor who lives outside Ontario can act, but security may be required. Letters probate may not be granted to a person who lives outside Ontario and outside the Commonwealth unless they give the same security (a bond) an administrator would, or a judge dispenses with or reduces it in special circumstances.

Where you live matters. Ontario.ca states that a bond is needed for a named executor only when the applicant does not live in Ontario, another province or territory, or a Commonwealth country. Administrators are different: letters of administration may not be granted to a person not residing in Ontario, except when resealing letters. Every person granted administration must give a bond the judge requires, except a surviving spouse on an intestacy whose net estate does not exceed the preferential share, if an affidavit of debts is filed.

An applicant can ask the court to dispense with or reduce the bond, or to limit security to Ontario assets. Small estates have their own rule, and a non-Commonwealth executor may still need security. The answer depends on where you live, whether there is a will, and the size of the estate, so a lawyer can confirm what applies to you.