Ontario mortgage help

Co-signing a mortgage in Canada

A mortgage co-signer or joint borrower is not merely providing a reference. Joint borrowers are responsible for the debt, and the mortgage can affect their credit, cash flow, assets, estate, and ability to borrow.

Reviewed September 1, 2026Published by Ontario Mortgage HelpHow we review

What to do first

  1. Ask the lender and your own lawyer to explain whether you will be a co-borrower, guarantor, registered owner, or some combination of those roles.

  2. Review the complete mortgage, purchase, title, insurance, tax, and ownership documents rather than only the payment arrangement within the family.

  3. Test whether you could carry the required payments and property obligations if the other borrower could not pay.

  4. Document how payments, expenses, sale decisions, refinancing, removal from the mortgage, death, disability, and disputes will be handled.

Important considerations

Responsibility is not divided by a private promiseFCAC states that joint borrowers are equally responsible for the unpaid balance. A family agreement does not necessarily limit the lender's contractual rights.

Removal is not automaticA co-signer generally cannot simply withdraw later. The lender may require a new application, refinance, sale, or other approved change.

Ownership and borrowing are different questionsBeing on title can create separate legal, tax, estate, and family-law consequences. Obtain advice based on the proposed structure.

Official sources