Caution, guarantor or co-borrower: what are the differences?

08 Apr 2026

When it comes to taking out a loan in Canada, it is essential to understand the roles and responsibilities associated with the terms “co-signer,” “guarantor,” and “co-borrower.” While these terms are sometimes used interchangeably, they refer to distinct legal commitments. This article aims to clarify these differences, through concrete examples and practical advice.

1. The co-borrower: a solid financial partner

A co-borrower is a person who, alongside the main borrower, signs the loan agreement and shares the responsibility for repayment. The income and financial situation of the co-borrower are taken into account to determine the total borrowing capacity. In case of default, the lender can look to either the main borrower or the co-borrower for repayment of the debt.

Concrete example: If a couple wants to buy a house and their combined income is not enough to obtain the desired loan, one of the partners can act as a co-borrower. This helps increase borrowing capacity and fairly share the repayment obligations.

2. The guarantor: security for the lender

The guarantor is a person who agrees to repay the borrower's debt in case of the borrower's default. Unlike the co-borrower, the guarantor is not a party to the initial loan contract and does not use the borrowed funds. Their role is to secure the lender by providing an additional guarantee.

Concrete example: A parent can act as guarantor for their child student who wants to rent an apartment. If the student does not pay their rent, the landlord can turn to the guarantor to recover the amounts owed.

3. The surety: a form of personal guarantee

The surety is a commitment by which a person agrees to pay the debt of a third party if that person does not do so. It is often used in lease contracts. There are two types of surety:

Simple surety: The owner must first pursue the tenant before turning to the guarantor. The guarantor only pays as a last resort.
Joint and several surety: The owner may demand immediate payment of the rent from the guarantor without going through the tenant. The guarantor is liable for all lease debts.

Concrete example: When a student rents an apartment, their parents can act as joint and several surety. If the student does not pay the rent, the landlord can directly demand payment from the parents, without first pursuing the student.

4. Key differences between the caution (surety), guarantor, and co-borrower

Contractual commitment: The co-borrower is an integral party to the loan contract, while the guarantor and the surety are external commitments to the initial contract.
Financial responsibility: The co-borrower shares full repayment responsibility from the start. The guarantor and surety only intervene in case of default by the main borrower.
Use of funds: The co-borrower uses the borrowed funds jointly, whereas the guarantor and surety do not directly benefit from the funds.

5. Practical tips

Risk assessment: Before acting as a guarantor or surety, carefully assess your ability to assume this responsibility in case of the borrower's default.
Transparent communication: Have an open discussion with the borrower about your expectations and the implications of your commitment.
Legal consultation: If in doubt, consult a legal professional to fully understand the legal implications of your commitment.

Sources

The information in this article is for general purposes only and may not reflect current laws or regulations. Verify any details with a qualified professional before making decisions. Some portions may have been created with AI assistance and should be confirmed for accuracy.

Written by Karine Haché

Mortgage broker