- A sunset clause is a term built into a marriage contract that limits how long all or part of the contract applies.
- A sunset clause usually comes from a specific worry: that a contract negotiated early in a relationship — sometimes under time pressure before a wedding — shouldn't necessarily govern a…
- Simply labelling a clause a "sunset" or "expiry" provision doesn't place it outside that scrutiny.
Some couples negotiating a marriage contract want protection now, but not forever — the idea that after enough years together, the contract should stop applying, or shift to something closer to what the default law would provide anyway. That's the idea behind a sunset clause: a term that says all or part of the marriage contract expires after a set period of time, or once a specific event happens. It sounds simple. Whether Ontario courts will actually treat a marriage contract as expired just because a sunset clause says so is a genuinely less settled question than most people assume.
This guide explains what a sunset clause typically says, why couples ask for one, and why "does it expire" isn't quite the right way to think about enforceability.
What a Sunset Clause Actually Says
A sunset clause is a term built into a marriage contract that limits how long all or part of the contract applies. It can be structured a few different ways, and the structure matters for how it will likely be read later.
| Type | How it's triggered | Example of what it might address |
|---|---|---|
| Time-based | A set number of years of marriage passes | The contract's property terms no longer apply after that period |
| Event-based | A specific life event occurs | The birth of a child, buying a home together, or a significant career change triggers a change in terms |
| Partial sunset | Some terms expire, others remain permanent | A support waiver might sunset while property terms remain |
Why Couples Ask for One
A sunset clause usually comes from a specific worry: that a contract negotiated early in a relationship — sometimes under time pressure before a wedding — shouldn't necessarily govern a marriage that lasts decades and changes in ways nobody could have predicted at signing. It can also be a negotiating tool, making a contract more palatable to a spouse who's uneasy about signing something permanent.
Do Ontario Courts Actually Enforce Them?
This is the honest, complicated answer: a sunset clause is a term of the contract, and like any other term, its enforceability depends on the same principles that apply to the contract generally — whether it was properly signed, whether both spouses understood it, whether there was proper financial disclosure, and whether enforcing it, or not enforcing it, would be unconscionable given how circumstances have actually unfolded. Simply labelling a clause a "sunset" or "expiry" provision doesn't place it outside that scrutiny.
There is no guarantee that a court will treat a marriage contract as fully expired just because a stated number of years has passed, especially if enforcing the expiry would produce an outcome that looks unfair on the specific facts. At the same time, there's also no rule that a sunset clause is automatically ineffective. This genuinely depends on how the clause is written and the circumstances at the time it matters — which is exactly why couples shouldn't treat a sunset clause as a simple, guaranteed "off switch."
What This Means for Drafting
- [ ] Be specific about exactly what expires and what, if anything, replaces it — a vague sunset clause is harder to apply than a detailed one
- [ ] Consider a review date instead of, or alongside, a hard expiry — a point where the couple agrees to revisit the contract rather than assuming it simply disappears
- [ ] Address what happens to the rest of the contract if only one term, like a support waiver, is meant to sunset
- [ ] Keep records of the circumstances at signing, since a court assessing enforceability later will look at what each spouse knew and understood at that time, not just years later
- [ ] Get advice on whether a sunset clause actually serves your goals, or whether it risks undermining the certainty the rest of the contract was meant to provide
Frequently asked questions
If our prenup has a sunset clause after a set number of years, does it just disappear once that time passes?
Not automatically in a guaranteed sense. The clause is still subject to the same enforceability review as any other contract term, so while it can and often does have the intended effect, there's no absolute guarantee it will be applied exactly as written in every circumstance.
Is it better to have a sunset clause or no expiry at all?
There's no universally right answer — it depends on what the couple is trying to achieve. Some couples prefer certainty with no expiry; others want the flexibility a sunset clause is meant to provide. This is worth discussing with a lawyer against your specific goals rather than defaulting to either option.
Can we set the contract to review, rather than expire, after a certain point?
Yes — a review clause, where the couple agrees to revisit and potentially update the contract at a set point, is a common alternative to a hard sunset clause and can avoid some of the uncertainty around whether an expiry will be enforced as written.
Does a sunset clause apply to child-related terms too?
Domestic contract terms dealing with parenting arrangements are treated differently in general — courts assess those based on the child's best interests at the relevant time regardless of what a contract says, so a sunset clause is really only meaningful for terms like property and spousal support.
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