Creating a prenup is one thing. Creating one that actually holds up in court is another. Every year, Canadian courts set aside marriage contracts because of procedural failures, inadequate disclosure, or terms that cross the line into unfairness. These aren’t obscure edge cases. They’re common, preventable mistakes.
Here’s your complete enforceability checklist.
1. Put It in Writing
This seems obvious, but it’s a legal requirement under Ontario’s Family Law Act. A verbal agreement about property division or spousal support is not a marriage contract. It must be a written document.
2. Both Parties Must Sign
Both partners must sign the same document. Digital signatures are generally acceptable in Ontario, but physical signatures with a witness are the safest approach.
3. Get It Witnessed
Each signature must be witnessed by at least one person. The witness should be a neutral third party, not a family member or someone with a financial interest in the outcome. Each witness should also sign a sworn statement confirming they saw the partner sign voluntarily.
4. Complete Full Financial Disclosure
Both partners must provide complete, honest financial disclosure before signing. Attach net worth statements to the agreement as schedules. Include income, assets, debts, business interests, pensions, and expected inheritances.
5. Get Independent Legal Advice
Each partner should consult their own lawyer before signing. The lawyer should provide a certificate of ILA confirming the client understood the agreement. While not legally required in Ontario, ILA is the strongest protection against future challenges.
6. Sign Well in Advance of the Wedding
Allow at least 30 days between signing and the ceremony. More time is better. Signing the night before the wedding virtually guarantees a duress argument.
7. Ensure the Terms Are Fair
Ontario courts can set aside provisions they find unconscionable. The agreement doesn’t need to be perfectly equal, but it should be reasonable. Both partners should benefit from the terms in some way, and neither should be left destitute.
8. Don’t Include Child Custody
Canadian law prohibits prenups from addressing decision-making responsibility, or parenting time. Including these provisions doesn’t just result in those clauses being struck. It can undermine the credibility of the entire agreement.
9. Include a Severability Clause
A severability clause specifies that if one provision of the agreement is found unenforceable, the remaining provisions survive. Without this clause, a single bad provision could void the entire contract.
10. Review and Update Periodically
A prenup signed at age 28 may not reflect your life at age 45. Including a review schedule and updating the agreement after major life changes strengthens enforceability and demonstrates that both parties intend the terms to remain fair.
The Checklist Summary
Written. Signed. Witnessed. Disclosed. Independently advised. Timed properly. Fair. No custody. Severable. Reviewed. Hit all ten, and your prenup is as close to bulletproof as Canadian law allows.
Bonus: Keep a Paper Trail
Beyond the checklist itself, document the process. Save copies of all financial disclosure documents. Keep records of when each partner received the draft, when they consulted their lawyers, and when they signed. If a dispute ever arises about whether the process was fair, a clear paper trail is your best defence.
Some couples include a recital section at the beginning of the agreement that describes the process: when the agreement was first discussed, when disclosure was exchanged, when each party received ILA, and confirmation that both parties signed voluntarily without duress or pressure. This narrative section can be persuasive evidence if the agreement is ever challenged. To see how I Do Prenup builds these safeguards into the process, visit How It Works.
What About “Unforeseen Circumstances”?
One challenge even well-drafted prenups face is the argument that circumstances have changed so dramatically since signing that enforcing the agreement would be unconscionable. Courts in Ontario have the power to set aside provisions on this basis, even if the original agreement was perfectly executed.
The best defence against this argument is building flexibility into the agreement itself. Include escalation clauses that adjust terms based on the length of marriage. Include review provisions that require periodic reassessment. Include conditional clauses that activate when specific life events occur (children, career changes, relocations). The more adaptive your agreement, the harder it is to argue that it’s become unfair over time.
Build an enforceable agreement from the start. Get started at I Do Prenup.
Frequently Asked Questions
Q: What’s the minimum requirement for a valid prenup in Ontario?
Under the Family Law Act: in writing, signed by both parties, and witnessed. However, meeting only the minimum significantly increases the risk of the agreement being set aside.
Q: Can a court throw out my prenup even if we followed all the rules?
In rare cases, yes. Courts retain discretion to set aside provisions that are unconscionable or that would result in one spouse qualifying for social assistance. Following the full checklist dramatically reduces this risk.
Q: Do I need a severability clause?
It’s not legally required, but it’s strongly recommended. Without one, a single unenforceable provision could potentially void the entire agreement.