Is Your Marriage Contract Valid? What Ontario Courts Look For

Signing a marriage contract does not guarantee it will be enforced. Ontario courts have the power to set aside marriage contracts that do not meet the required legal standards. If you are relying on a contract to protect your assets, you need to know what makes it valid — and what could defeat it.

The Legal Framework

Under Ontario’s Family Law Act, a court can set aside a domestic contract (including a marriage contract) if:

• A party failed to disclose significant assets or debts before signing
• A party did not understand the nature or consequences of the contract
• The contract was signed under duress or undue influence
• Otherwise under the common law

Each of these grounds is worth examining carefully.

1. Failure to Disclose Financial Information

This is the most common ground for setting aside a marriage contract.

Before signing any marriage contract, both parties must fully and honestly disclose their financial situation — assets, debts, income sources, and anything else financially relevant. The disclosure should be comprehensive.

A contract can be set aside if one party hid significant assets, understated liabilities, or otherwise misrepresented their financial position before signing. This applies even if the other party did not specifically ask about those assets.

Practical risk: If you signed a marriage contract without receiving complete financial disclosure from your partner, the contract may be vulnerable to challenge — even years later.

2. No Independent Legal Advice

Each party should have their own lawyer — not a shared lawyer — review the contract and explain its legal consequences before signing. This is called independent legal advice (ILA).

Without ILA:

• One party may not fully understand what they are agreeing to
• The court may conclude that consent was not truly informed
• The contract is at greater risk of being set aside

Common pitfall: One spouse’s lawyer drafts the contract, and the other spouse signs without obtaining their own counsel. This creates a significant risk that the contract will not be upheld.

3. Duress or Undue Influence

A contract signed under coercion — whether physical threats, emotional manipulation, or severe time pressure — may not represent free and voluntary consent.

Courts pay particular attention to:

• Timing: A contract signed days before the wedding, with significant social or family pressure to proceed, may raise concerns about whether consent was truly voluntary
• Imbalance of power: A contract signed in circumstances where one party had much more bargaining power, legal sophistication, or financial knowledge than the other

This does not mean every late-stage contract is invalid — but the circumstances of signing matter.

4. The Contract Does Not Understand the Nature of the Agreement

If one party did not understand what they were signing — perhaps because of a language barrier, lack of sophistication, or inadequate explanation — the court may find that informed consent was absent.

This is particularly relevant in cases involving parties whose first language is not English and who signed a contract without a clear explanation in their own language.

What Happens If the Contract Is Set Aside?

If a court sets aside a marriage contract, the parties are treated as if no contract existed. Ontario’s default equalization of net family property rules apply.

This can have enormous financial consequences — particularly for the party who expected to benefit from the contract’s protection.

The Matrimonial Home Provisions: Extra Scrutiny

Provisions that attempt to remove the matrimonial home from the equalization calculation receive particularly close scrutiny. Ontario courts have sometimes refused to enforce such provisions where the circumstances have changed significantly or where the provision would produce an unjust result.

How to Make Your Contract Stronger

1. Draft it early — months before the wedding, not days
2. Require full financial disclosure from both parties, with documentation
3. Ensure each party gets their own independent lawyer
4. Use clear language — ideally reviewed and explained in each party’s preferred language
5. Do not rush — give both parties adequate time to review and consider

Practical Advice

If you are relying on a marriage contract to protect significant assets, have it reviewed by an experienced family law lawyer — even if it was prepared some time ago. The earlier you identify any vulnerabilities, the more options you have to address them.

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This article was written by Miao He (何淼), Ontario lawyer (LSO #83315K) and China-licensed lawyer, focusing on family law for the Chinese-Canadian community in the GTA.