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This article provides general information about cohabitation agreements and marriage contracts in Ontario as of 2026 and is not legal advice. Statutory references are to the consolidated Family Law Act, R.S.O. 1990, c. F.3 (consolidation from 1 May 2026) and the Succession Law Reform Act, R.S.O. 1990, c. S.26, both read on 26 September 2026. Cases are quoted from the courts' own published judgments.
A cohabitation agreement Ontario couples sign is usually written in the weeks around a move: two leases ending, one set of keys, a mortgage application with both names on it. Nobody is planning a breakup. They are deciding what happens to the things each of them is carrying in, and they want the answer written down while they still agree on it.
The law gives that document a narrow job and a long reach: it can decide who owns the condo and whether support is ever paid, but not where the children live. So this cohabitation agreement Ontario guide is organised around the promises couples actually try to write down, one section per promise, with the verdict the Family Law Act gives each. Our overview of the family-law situations where a lawyer earns their fee covers the wider ground.
Cohabitation agreement Ontario: the answer in six lines
A cohabitation agreement and a marriage contract are the same kind of document signed at different points in a relationship, and the same few sections of one statute limit both.
- Two contracts, one Act. Unmarried partners who live together, or intend to, sign a cohabitation agreement under s. 53 of the Family Law Act. Married or engaged couples sign a marriage contract under s. 52. "Prenup" is the everyday word for a marriage contract signed before the wedding.
- Marrying converts it. If the partners to a cohabitation agreement marry each other, s. 53 (2) deems it a marriage contract, with no new signature.
- Three formalities. Under s. 55 (1) it has to be in writing, signed by both of you and witnessed. A lawyer is not a legal requirement, as Steps to Justice states plainly.
- Two things it cannot touch. Decision-making responsibility and parenting time are excluded by ss. 52 (1) (c) and 53 (1) (c), and a marriage contract cannot limit a spouse's right to live in the matrimonial home (s. 52 (2)).
- Unmarried partners start with nothing shared. Ontario's guidance on dividing property says "common law couples are not legally required to split property acquired when they lived together". A cohabitation agreement is the only document that can give them a sharing rule.
- It can be set aside. Under s. 56 (4) a court can undo a contract where significant assets or debts were not disclosed, where a party did not understand it, or under ordinary contract law.
Three names for two contracts, and where a prenup fits
Ontario law knows two contracts for couples who are still together, and the calendar decides which one you are signing.
Of the five kinds of "domestic contract" in s. 51 of the Family Law Act, only the marriage contract and the cohabitation agreement are made while a relationship is working. A prenuptial agreement in Ontario is not a separate legal category. Section 52 (1) lets "two persons who are married to each other or intend to marry" make a marriage contract, so a prenup is a marriage contract signed before the wedding and a postnuptial agreement is the same contract signed afterwards.
The timing matters more than the name. At three points in an ordinary relationship the law changes what it does by default, and a contract written at the first stop keeps working through the later ones.
Ontario · as of 2026
Five stops in a relationship, and what the law does at each one
Moving in
Contract
A cohabitation agreement can be signed now, or even before, by people who “intend to cohabit”.
FLA s. 53 (1)
Without one
- No property sharing by statute.
- Each keeps what is in their own name; a claim to the rest is judge-made.
FLA s. 1 (1); Kerr v. Baranow
Three years together, or a child
Contract
The same cohabitation agreement still governs. Nothing new is needed.
FLA s. 53 (1)
Without one
- A spousal support obligation switches on.
- So does a dependant's support claim against an estate.
FLA s. 29; SLRA s. 57
Engaged
Contract
A marriage contract becomes available to anyone who “intend[s] to marry”.
FLA s. 52 (1)
Without one
- Nothing changes until the wedding itself.
Wedding day
Contract
Any cohabitation agreement is automatically deemed a marriage contract. A new one can still be signed during the marriage.
FLA ss. 53 (2), 52 (1)
Without one
- Equalization of net family property applies.
- Both spouses get an equal right to live in the matrimonial home.
- An intestate share of the estate.
- An existing will is no longer revoked by the marriage.
FLA Part I, s. 19 (1); SLRA Part II; SLRA s. 15 (a) repealed 2022
Separation
Contract
The only contract left is a separation agreement, the one instrument that can settle parenting and release home rights.
FLA ss. 54, 21 (1) (b)
Without one
- Clocks start: six years from separation, or two after a divorce, to claim equalization.
FLA s. 7 (3)
The last stop belongs to a different document. Once a couple has separated, they sign a separation agreement under s. 54, the only domestic contract that may deal with decision-making responsibility and parenting time. A cohabitation agreement Ontario partners wrote years earlier often becomes the starting point for that negotiation.
What Ontario does if you sign nothing
Married couples in Ontario get a complete statutory property regime. Unmarried couples get almost none, and that gap is the main reason cohabitation agreements exist.
For a married couple, Part I of the Act applies: on separation, the spouse with the smaller net family property "is entitled to one-half the difference between them" (s. 5 (1)). Part II gives both spouses an equal right to live in the matrimonial home whoever holds title (s. 19 (1)), and on an intestate death a married spouse takes a statutory share under the Succession Law Reform Act.
None of that reaches a common law separation in Ontario. The Act's definition of "spouse" in s. 1 (1) means people married to each other, so Parts I and II never apply to an unmarried couple, however long they lived together. Steps to Justice's page on common-law property puts it plainly: "Married couples usually share the value of their property if they separate or divorce. This is not true for common-law couples, who have different rights." It also warns that unjust enrichment and resulting trust claims "can be very hard to prove".
Those judge-made claims are what remain. In Kerr v. Baranow, 2011 SCC 10, the Supreme Court of Canada said that for unmarried partners "in most common law provinces, judge-made law was and remains the only option", and set out the "joint family venture" test for unjust enrichment.
Common law rights in Ontario are not zero, though. Part III uses a wider definition in s. 29: partners who have cohabited continuously for at least three years, or in a relationship of some permanence as the parents of a child, fall under the same support obligation as married spouses. The default is lopsided in a way few couples expect. A court can order support after three years and still has no power to divide their property.
That default covers a lot of households. In the 2021 Census Ontario had the lowest share of common-law couples of any province, 15.7% against 42.7% in Quebec, according to Statistics Canada's July 2022 census release on couples. The share has still more than tripled since 1981, and it now means 515,395 Ontario couples living outside the statutory property rules, 189,835 of them with children at home. It is the gap a cohabitation agreement Ontario partners sign is built to fill.
Statistics Canada · Census 1981 to 2021
Share of couples living common law
515,395
common-law couples in Ontario, 2021 Census
189,835
of them with children at home (36.8%)
12%
of couples in the Toronto metropolitan area live common law
Ten promises, and the verdict on each
Most of what couples want in a domestic contract is allowed. The exceptions follow a pattern: anything about children stays open to a court, and a married couple's right to live in their home cannot be signed away before separation.
The sheet takes ten clauses as couples tend to phrase them and marks what the Act does with each. The next five sections take the promises where the money and the surprises are.
Schedule A · draft clauses
Ten things couples want in writing, and what Ontario law does with each
Tap a clause to see the section that decides it.
"What I owned before we met stays mine"
This promise holds, but for a married couple it is worth far more than most people realise, because of one exception buried in a definition.
The Act already protects some of what you bring into a marriage. Each spouse deducts the value of property owned on the wedding day, "other than a matrimonial home" (Family Law Act, s. 4 (1)). That phrase is the trap. If the condo you owned before the wedding is where you both live when you separate, its wedding-day value is not deducted, and its whole value on the separation date goes into your side of the calculation. The same money held in an investment account would have kept its deduction.
Consider Daniel, who owned a semi in Hamilton worth $500,000 when he married and still lives there with his wife when they separate, by which time it is worth $700,000. Each of them has another $100,000 in savings. With no marriage contract, his net family property is $800,000 and hers is $100,000, so he owes her an equalization payment of $350,000. Had the same $500,000 sat in investments, he would owe $100,000. A marriage contract excluding the house under s. 4 (2), paragraph 6, would bring it to nothing. The calculator runs the same arithmetic on your numbers.
Interactive · Ontario Family Law Act, Part I
One asset brought into a marriage, five answers at separation
Move the sliders. Each bar is the equalization payment the Act produces under a different arrangement, from the same four numbers.
A condo, a house, or savings one spouse owned before marrying.
The valuation date is usually the separation date.
Everything else in the owner's name, less debts.
Everything in the other spouse's name, less debts.
No contract, and it became the family home
Owner pays$350,000
The wedding-day deduction is lost, so the whole value at separation is shared.
FLA s. 4 (1): the deduction excludes a matrimonial home
No contract, and the same money stayed invested
Owner pays$100,000
The wedding-day value is deducted. Only the growth during the marriage is shared.
FLA s. 4 (1): date-of-marriage deduction
Marriage contract restores the wedding-day deduction
Owner pays$100,000
The home is treated as if it were any other asset you brought in.
FLA ss. 4 (2) para. 6 and 52 (1) (a)
Marriage contract excludes the asset, growth and all
$0
Nothing about it enters the calculation.
FLA ss. 4 (2) para. 6 and 52 (1) (a)
Never married, no cohabitation agreement
No statutory claim
Part I of the Act does not apply. Any claim is a judge-made trust or unjust enrichment claim.
FLA s. 1 (1) “spouse”; Kerr v. Baranow, 2011 SCC 10
The same exception reaches gifts and inheritances. Property a spouse receives by gift or inheritance from a third person during the marriage is excluded from net family property, but again "other than a matrimonial home" (s. 4 (2), para. 1), so a parent's help with the down payment on the home a married couple lives in generally loses that protection. A marriage contract can keep it out. Section 57 adds a useful detail: if the contract says a specific gift cannot be sold or mortgaged without the donor's consent, the parents are deemed a party to the contract for that clause and can enforce it themselves.
How the home is registered on title, as joint tenants or tenants in common, is a separate decision made at the purchase, and a real estate lawyer's closing fees in Ontario include advising on it. Ideally the contract and the title say the same thing.
"If we split up, you move out"
A marriage contract cannot make this promise. Ownership can be settled in advance; the right to stay in the home cannot.
Section 19 (1) of the Family Law Act gives both spouses "an equal right to possession of a matrimonial home", whoever is on title, and s. 52 (2) makes a marriage contract provision "purporting to limit a spouse's rights under Part II" unenforceable. So Daniel's contract can say the house and its value stay with him, but it cannot say his wife leaves the day they separate. If they cannot agree who stays, a court can order exclusive possession to one of them under s. 24.
The only contract that can release these rights is a separation agreement (s. 21 (1)). Part II does not apply to unmarried couples, but a move-out clause in a cohabitation agreement sits under s. 53 (2): if the couple later marries, it becomes a marriage contract clause and unenforceable.
"Neither of us will ever ask for support"
A support waiver is allowed and usually holds, but it is the clause with the most named ways back into court.
Both contracts may settle "support obligations" (ss. 52 (1) (b), 53 (1) (b)), which includes waiving them. Section 33 (4) then lets a court set aside a support provision or waiver, even if the contract says the section does not apply, where it "results in unconscionable circumstances", where the person who waived qualifies for support out of public money, or where support under the contract is in default. For a married couple who later divorce, s. 15.2 (4) (c) of the Divorce Act also has the court consider "any order, agreement or arrangement relating to support" as one factor among several.
A waiver signed at 29 by two people with similar careers can look very different at 49, after one of them stepped back from work to raise children, and a clause that adjusts with the length of the relationship or the arrival of children is one way to anticipate that. How the Advisory Guidelines would price the claim a waiver gives up is set out in our guide to spousal support in Ontario.
"The children will live with me"
This promise is outside what either contract can decide, and child support terms bind only while they are reasonable.
The words are explicit. Sections 52 (1) (c) and 53 (1) (c) of the Family Law Act allow a contract to deal with "the right to direct the education and moral training of their children, but not the right to decision-making responsibility or parenting time". Even the part that is allowed stays open: s. 56 (1) lets a court disregard a provision about education, moral training or parenting where "to do so is in the best interests of the child". Our guide to child custody in Ontario explains how that test works once parents separate.
Child support follows the same logic. Section 56 (1.1) lets a court disregard a child support provision that is "unreasonable having regard to the child support guidelines", so the table amount in our child support in Ontario guide is the benchmark any agreed figure is measured against.
"If I die first, the will decides"
A domestic contract can settle rights on death, and since 2022 a wedding no longer cancels the will that sits alongside it.
Both sections allow agreements about rights "on death". For a married couple that matters because of the election in s. 6: the surviving spouse chooses between what the will or the intestacy rules give them and an equalization payment, and has six months from the death to file that election (s. 6 (10)). A marriage contract can take the choice off the table, which is often the point in a second marriage where each spouse wants their estate to reach children from an earlier relationship.
Two limits apply. A court may still order support for a dependant out of an estate "despite any agreement or waiver to the contrary" (Succession Law Reform Act, s. 63 (4)), and "spouse" there includes an unmarried partner who meets the three-year or child test. And a promise to leave something by will is not a will.
Since s. 15 (a) of the Succession Law Reform Act was repealed on 1 January 2022, marriage no longer revokes an existing will, so a will written for an earlier life can quietly survive a new marriage. Our guide to estate planning in Ontario sets out which document wins when two disagree, and how to make a will in Ontario covers the will itself. For unmarried partners the gap is starker: the intestacy rules use the married-only definition of spouse, so a common-law partner takes no share of an estate left without a will.
Why a marriage contract signed two days before the wedding failed
Section 56 (4) gives three grounds to set a domestic contract aside, and the Court of Appeal's leading case on a marriage contract shows how they come together when a contract is rushed.
The rules that apply to every domestic contract are in our separation agreement guide. What a prenup adds is timing. In LeVan v. LeVan, 2008 ONCA 388, the contract was signed on 20 June 1996, two days before the wedding. The husband's disclosure listed his interest in the family companies without values, and his lawyer described his interest in the family trust as having "very minimal value" at the date of marriage, while the wife's valuator later put the trust's holdings at $30 million. A second lawyer, brought in after her first objected, met her for about an hour without financial disclosure, and the court found she "was in no position to advise the wife in a meaningful way about the marriage contract."
The trial judge set the contract aside for non-disclosure, and the Court of Appeal upheld it, describing a two-stage test: first whether a s. 56 (4) circumstance is made out, then "whether it is appropriate to exercise discretion in favour of setting aside the agreement" (para. 51). The contrast is Hartshorne v. Hartshorne, 2004 SCC 22, a British Columbia case under a different statute, where the Supreme Court upheld an agreement signed on the wedding day and said courts should respect such arrangements, "particularly where the agreement in question was negotiated with independent legal advice."
Independent legal advice in Ontario: what the second lawyer is for
Independent legal advice is not required for a valid domestic contract, but it is the best evidence available later that both of you understood what you signed.
Nothing in s. 55 (1) mentions lawyers. Steps to Justice, the public legal information service run by Community Legal Education Ontario, says: "You do not need a lawyer to make a cohabitation agreement. But it's a very good idea for each of you to get your own legal advice before signing one." It adds that "you and your partner should not go to the same lawyer", which ties to s. 56 (4) (b), the ground for a party who "did not understand the nature or consequences" of the contract.
The reason for two lawyers comes from the conduct rules. The Federation of Law Societies' Model Code, the national model every Canadian law society's rules are drawn from, says a lawyer acting for more than one client must warn them that nothing one says is confidential from the other (rule 3.4-5), and its commentary to rule 3.4-7 says a lawyer should avoid acting for both "when it is likely that a contentious issue will arise between them". A contract about dividing property on a breakup fits.
On price, there is no reliable published figure for independent legal advice in Ontario or for a whole domestic contract, and this page will not invent one. What can be verified: JusticeNet, a not-for-profit for people who earn too much for legal aid, lists lawyers at $130 to $200 an hour by household income, noting that "this is an hourly rate, not the total cost of a case". The Law Society Referral Service offers a free consultation of up to 30 minutes, explained in our guide to the lawyer referral service in Ontario. Domestic contracts are not among the family services Legal Aid Ontario lists. The table shows what drives the hours instead.
| What is on the table | What tends to drive the lawyer's time | What it protects against |
|---|---|---|
| Financial disclosure from both of you | Statements, pensions, business interests and valuations to read | A set-aside for non-disclosure, s. 56 (4) (a) |
| Drafting the contract | How many assets are excluded, how support and the home are handled | Clauses that fail under ss. 52 (2), 56 (1) or 56 (2) |
| Independent legal advice for the other partner | Explaining each clause and what is given up | A set-aside for lack of understanding, s. 56 (4) (b) |
| Negotiation between two lawyers | How far apart you are, and how many drafts it takes | Pressure or unfairness claims under s. 56 (4) (c) |
Flat fees, hourly billing and retainers are explained in our guide to what a lawyer costs in Ontario.
When a prenuptial agreement lawyer or cohabitation agreement lawyer earns the fee
The situations below are where a careful draft tends to pay for itself.
- One of you owns a home, or will before the wedding, because of the matrimonial home rule in s. 4 (1).
- A parent is helping with a down payment, or an inheritance is expected, which a gift clause and s. 57 can protect.
- There is a business, a practice or a pension that needs valuing and excluding.
- Either of you has children from an earlier relationship and wants the estate to reach them.
- One of you may step back from paid work, where a flat support waiver is most exposed under s. 33 (4).
- The wedding is close. LeVan is the reason to finish weeks ahead, not days.
- You are unmarried and plan to stay that way, because the default shares no property at all.
A prenuptial agreement lawyer usually drafts for one partner while a second lawyer advises the other, and a cohabitation agreement lawyer does the same job under s. 53. Our guide to how to find a lawyer in Canada covers what to ask at a first meeting, and how much a divorce costs in Ontario shows what a contested property dispute costs by comparison.
How Olanur helps
We built Olanur so the first call is the right one. You describe what you are dealing with once, and our matching system connects you with verified Ontario family lawyers who draft and review domestic contracts. Matching is free, and each lawyer sets their own fees, which you see before you book.
A domestic contract usually needs two lawyers, and Olanur can match each partner separately so the advice stays independent. If one of you already has a draft, a lawyer can review the document and give the independent legal advice, or you can get matched with a family lawyer to draft the agreement from the start.
Frequently asked questions
Yes. A cohabitation agreement Ontario partners sign is binding if it meets s. 55 (1) of the Family Law Act: in writing, signed by both and witnessed. A court can still set it aside under s. 56 (4) for non-disclosure of significant assets or debts, lack of understanding, or ordinary contract-law grounds, which is why disclosure and separate advice matter.
There is no legal difference. The Family Law Act uses the term marriage contract (s. 52) for an agreement between people who are married or intend to marry. A prenup is a marriage contract signed before the wedding, and a postnuptial agreement is one signed after it. The same rules and limits apply to both.
Under s. 53 (2) of the Family Law Act, it is deemed to be a marriage contract once the partners marry each other. It keeps working without a new signature, but the marriage-contract limits then apply, including s. 52 (2), which makes a clause limiting a spouse's right to live in the matrimonial home unenforceable.
No. Sections 52 (1) (c) and 53 (1) (c) exclude decision-making responsibility and parenting time from marriage contracts and cohabitation agreements. A contract may address education and moral training, but a court can disregard even that where it is in the child's best interests (s. 56 (1)). Parenting is settled at separation.
Not automatically. Part I of the Family Law Act applies only to married spouses, and Ontario's government guidance says common-law couples are not legally required to split property acquired while living together. A partner may bring an unjust enrichment claim, which can be hard to prove, or the couple can set their own rules in a cohabitation agreement.
It is not a legal requirement, but it is the usual practice and the strongest safeguard. Steps to Justice advises each partner to get their own legal advice and not use the same lawyer, and a partner without advice may struggle to argue later that they did not understand the contract under s. 56 (4) (b).
No reliable published source gives a total price, and fees depend on how much property there is to value and how many drafts it takes. For verified reference points, JusticeNet lists lawyers at $130 to $200 an hour for income-qualified clients, and the Law Society Referral Service offers a free first consultation of up to 30 minutes.
The conversation to have before the movers arrive
The best time to write a cohabitation agreement Ontario law will enforce, or a marriage contract, is when it feels least necessary: before the move, well before the wedding, while both of you still agree on what is fair. Most of it records what you already intend.
If one of you owns a home, expects a gift or an inheritance, or plans to stay unmarried, a conversation with a family lawyer before anything is signed is usually worth having. Olanur can match each of you with a verified Ontario family lawyer, free, so the advice on each side stays your own.
Priya Kapoor
Family, Real Estate & Criminal Law Contributor
Priya focuses on family law, real estate transactions, criminal defence, and civil disputes, guiding Canadians through some of the most consequential legal moments in their lives.
