Marriage contracts (prenups and postnups) let couples set expectations for property division, support, and financial responsibilities before or during marriage. In Ontario these agreements are powerful planning tools when done correctly — they can reduce conflict, protect business or inheritance assets, and provide certainty if the relationship ends. This guide explains what these contracts can (and cannot) do, legal requirements, and best practices for drafting enforceable agreements.
How Marriage Contracts Can Shape Outcomes
A valid marriage contract can change how property is divided and whether spousal support is paid — offering predictability and reduced legal costs if the marriage ends. Conversely, poorly drafted or unfair agreements risk being set aside by a court.
Legal Framework: Contracts under Ontario Law
Marriage contracts are governed by the Family Law Act and common-law principles. For enforceability, courts look at voluntariness, full financial disclosure, independent legal advice, and fairness at the time of signing and (in some cases) at the time of enforcement.
Key Elements Commonly Addressed
- What property is excluded from equalization (business, inheritance, premarital assets).
- Division of assets on separation or divorce.
- Spousal support: waiver, limitation, or formula for calculation.
- Debt responsibility and estate planning coordination.
What Marriage Contracts Cannot Do
- Contractual terms cannot determine decision making responsibility or child support (these are determined by the child’s best interests and statutory rules).
- Courts may override unfair terms affecting child welfare.
Precautionary Measures When Drafting Agreements
- Provide full, contemporaneous financial disclosure.
- Each party should have independent legal advice and time to consider the agreement.
- Avoid signing under duress or immediately before a wedding without adequate review.
Why Accurate Documentation Matters
Supporting schedules, valuations (for businesses or real property), and clear definitions reduce later disputes. Attach exhibits where necessary — e.g., a precise inventory of excluded assets.
Negotiation Strategies That Improve Enforceability
- Use neutral valuations for complex assets (businesses, pensions).
- Consider built-in review clauses for significant life events (birth of a child, major change in financial circumstances).
- Aim for fairness — grossly one-sided agreements are vulnerable to court challenge.
Limitations and Common Pitfalls
- Outdated agreements that don’t reflect current laws or circumstances can be contested.
- Hidden assets or misstatements may invalidate a contract.
- Emotional pressure or lack of time before signing increases risk of challenge.
When to Seek Professional Guidance
Work with family lawyers experienced in matrimonial agreements, and involve accountants or business valuators if your finances are complex.
A well-crafted marriage contract is a proactive way to manage financial risk and clarify expectations. When drafted fairly, transparently, and with proper legal advice, these agreements provide certainty and reduce future conflict.
Learn how to draft enforceable marriage contracts at our free webinar, Marriage Contracts, Prenups, and Postnups, on October 14 at 5PM ET. Family lawyers will discuss common clauses, mistakes to avoid, and drafting tips.
