Prenuptial agreements are legally recognized in Ontario and are governed by section 52 of the Family Law Act, R.S.O. 1990, c. F.3. In Ontario, a prenup is called a “marriage contract.” A marriage contract may be entered into before or during the marriage and can address a wide range of financial matters, provided it complies with the Act.

The Family Law Act, s. 52(1) provides:
“Two persons who are married to each other or intend to marry may enter into an agreement in which they agree on their respective rights and obligations under the marriage or on separation, on the annulment or dissolution of the marriage or on death.”

Marriage contracts can address:

• Ownership or division of property;
• Spousal support obligations;
• The right to direct the education and moral training of children (though courts may override this in the child’s best interests);
• Any other matter in the settlement of their affairs, except the right to possess the matrimonial home.

What makes a prenup enforceable in Ontario?

To be enforceable, a marriage contract in Ontario must meet both formal and substantive requirements.

Formal requirements:

• Must be in writing (oral agreements are not valid);
• Must be signed by both parties;
• Must be witnessed (the witness must also sign the agreement).

These requirements are set out in section 55(1) of the Family Law Act.

The Family Law Act, s. 55(1) provides
“A domestic contract and an agreement to amend or rescind a domestic contract are unenforceable unless made in writing, signed by the parties and witnessed.”

Substantive considerations:

The following are critical for enforceability:

• Full and frank financial disclosure by both parties at the time of signing;
• Independent legal advice (ILA) for both parties (strongly recommended but not mandatory);
• The agreement must not be unconscionable or made under duress, coercion, or undue influence.

The court may set aside a marriage contract under section 56(4) of the Family Law Act if:

• A party failed to disclose significant assets, debts, or liabilities;
• A party did not understand the nature or consequences of the agreement;
• The agreement is otherwise unconscionable.

The Family Law Act, s. 56(4) provides:
“A court may, on application, set aside a domestic contract or a provision in it,

(a) if a party failed to disclose to the other significant assets, or significant debts or other liabilities, existing when the domestic contract was made;

(b) if a party did not understand the nature or consequences of the domestic contract; or

(c) otherwise in accordance with the law of contract.”

Unique Ontario issues or considerations

Matrimonial Home Rules

Ontario has strict rules protecting the right to possession of the matrimonial home. Even if only one spouse owns the home, the other spouse cannot be excluded from possession during the marriage without a court order. A marriage contract cannot override this right.

The Family Law Act, s. 52(2) provides:
“A provision in a marriage contract purporting to limit a spouse’s rights under Part II (Matrimonial Home) is unenforceable.”

However, the contract can address division of the home’s value upon separation or death.

Equalization and Property Division

Ontario uses an equalization of net family property system, governed by Part I of the Family Law Act. A marriage contract can contract out of the equalization regime, allowing couples to:

• Exclude certain property (e.g., inheritances, business interests);
• Define custom valuation or division rules;
• Preserve pre-marital assets or their growth.

Inheritances, Gifts, and Excluded Property

Without a contract, inheritances or gifts received during the marriage are excluded from equalization if kept separate. If mingled (e.g., used to buy the matrimonial home), the exclusion may be lost. A marriage contract can strengthen these exclusions and prevent disputes over co-mingling.

You’re Invited to Call or E-Mail!

If you’re considering a prenuptial agreement — or have already made your decision — you’re invited to call or email us. We’ll explain for free how you can protect your assets and plan your estate. You can call us toll-free at (800) 837-0460 or email us using our contact form here. We can help you prepare an Ontario agreement.