Canada · ON · ca-on-marriage_contract-2026-09-12.1
Ontario marriage contract research: Family Law Act, R.S.O. 1990, c. F.3, ss. 52, 55, 56(4). Unmarried default: no automatic property.
Ontario has its own marriage-contract pack. Ontario marriage contract research: Family Law Act, R.S.O. 1990, c. F.3, ss. 52, 55, 56(4). Unmarried default: no automatic property. This is not a U.S. prenup and it is not a neighbouring province’s statute with the names swapped.
Ontario also has a cohabitation-agreement pack. Unmarried partners do not automatically receive the married property-division statute. This pack is the cohabitation track. Do not treat it as a marriage contract or as Swedish samboavtal.
The two instruments stay apart on purpose. A file titled prenup still has to be classified as a marriage contract or a cohabitation agreement based on whether the parties are married, about to marry, or unmarried, and on Ontario form.
marriage contract
A marriage contract must be in writing, signed by the parties, and witnessed. Ontario does not use Québec notarial form as the formation rule.
A marriage contract must be in writing, signed by the parties, and witnessed. Ontario does not use Québec notarial form as the formation rule.
Married spouses have a Part I equalization claim against net family property unless a valid domestic contract says otherwise within the Act’s limits. The matrimonial home has special treatment; a marriage contract cannot limit possessory rights in the matrimonial home in the way some other property clauses can.
A marriage contract typically addresses property, debts, and sometimes support between spouses. Public-order limits (Québec family patrimony; child support everywhere) still apply.
Spousal support can be addressed in a domestic contract, but later override under the FLA/Divorce Act remains a lawyer question. Do not treat a waiver as a court result.
Child support and custody/parenting cannot be bargained away as if they were ordinary property. Flag any child-support waiver for counsel.
s. 56(4) lists setting-aside grounds including failure to disclose significant assets or debts, failure to understand the nature or consequences of the contract, and other grounds in the law of contract. Independent legal advice is a practical and evidentiary issue, not a magic phrase that saves a contract.
The Supreme Court of Canada treated inadequate financial disclosure and exploitation of vulnerability as reasons a negotiated family agreement may not stand.
Do not import U.S. UPAA waiting periods or Swedish Skatteverket registration into Ontario analysis.
Canadian family agreements often stand or fall partly on whether each party could get advice. That is not a uniform statutory certificate across provinces, and Québec notarial counseling is a different professional model from common-law ILA letters.
A first draft delivered immediately before a wedding is a voluntariness and understanding fact. Canada does not use a single U.S.-style statutory waiting period in these packs.
cohabitation agreement
A cohabitation agreement must be in writing, signed by the parties, and witnessed (s. 55).
A cohabitation agreement must be in writing, signed by the parties, and witnessed (s. 55).
Equalization of net family property in Part I is a married-spouse machine. Unmarried partners do not get that statutory equalization. A cohabitation agreement is how they allocate property by contract. Some support rights can arise after three years of cohabitation or a child of the relationship.
A cohabitation agreement typically addresses property and debts between unmarried partners. It cannot manufacture a statutory regime the province does not confer, and it cannot replace a will.
Spousal support can be addressed in a domestic contract, but later override under the FLA/Divorce Act remains a lawyer question. Do not treat a waiver as a court result.
Child support and custody/parenting cannot be bargained away as if they were ordinary property. Flag any child-support waiver for counsel.
s. 56(4) lists setting-aside grounds including failure to disclose significant assets or debts, failure to understand the nature or consequences of the contract, and other grounds in the law of contract. Independent legal advice is a practical and evidentiary issue, not a magic phrase that saves a contract.
The Supreme Court of Canada treated inadequate financial disclosure and exploitation of vulnerability as reasons a negotiated family agreement may not stand.
Do not import U.S. UPAA waiting periods or Swedish Skatteverket registration into Ontario analysis.
Canadian family agreements often stand or fall partly on whether each party could get advice. That is not a uniform statutory certificate across provinces, and Québec notarial counseling is a different professional model from common-law ILA letters.
A cohabitation agreement signed years into a relationship, or a 'prenup' signed while unmarried just before a wedding, raises classification and transition questions. Marriage usually moves the couple onto the marriage-contract / marital-property statute.
Common questions
Married spouses have a Part I equalization claim against net family property unless a valid domestic contract says otherwise within the Act’s limits. The matrimonial home has special treatment; a marriage contract cannot limit possessory rights in the matrimonial home in the way some other property clauses can.
Equalization of net family property in Part I is a married-spouse machine. Unmarried partners do not get that statutory equalization. A cohabitation agreement is how they allocate property by contract. Some support rights can arise after three years of cohabitation or a child of the relationship.
A marriage contract must be in writing, signed by the parties, and witnessed. Ontario does not use Québec notarial form as the formation rule.
s. 56(4) lists setting-aside grounds including failure to disclose significant assets or debts, failure to understand the nature or consequences of the contract, and other grounds in the law of contract. Independent legal advice is a practical and evidentiary issue, not a magic phrase that saves a contract.
Child support and custody/parenting cannot be bargained away as if they were ordinary property. Flag any child-support waiver for counsel. Spousal support can be addressed in a domestic contract, but later override under the FLA/Divorce Act remains a lawyer question. Do not treat a waiver as a court result.
Worked examples
The useful question is whether it is a marriage contract or a cohabitation agreement given the parties’ status. Ontario sources are the only citations this page will use.
Ontario equalization language, British Columbia excluded-property language, and Québec family-patrimony language are not interchangeable. Do not import U.S. UPAA waiting periods or Swedish Skatteverket registration into Ontario analysis.
The Supreme Court of Canada treated inadequate financial disclosure and exploitation of vulnerability as reasons a negotiated family agreement may not stand.
For a lawyer