What is a separation agreement in Ontario?
A separation agreement is a written contract between spouses who have separated, married or common-law, that settles parenting, support and property issues without a court order. To be enforceable in Ontario it must be made in writing, signed by both of you and witnessed. A court can still set it aside if it was unfair in how it was made.
Key points
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It is a "domestic contract" under Part IV of Ontario's Family Law Act.
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You can settle everything stemming from your separation, or only the issues you agree on, and leave the rest for later.
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Full and frank financial disclosure and independent legal advice for each spouse are what make an agreement hard to challenge.
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Terms about children are always subject to the child's best interests.
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If filed with the court, its support terms can be enforced by the Family Responsibility Office just like a court order.
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We offer separation agreement drafting package at a $1,499 flat fee, plus HST.
Not sure where your situation fits? Book a free 15-minute call about your separation agreement.
What goes in a separation agreement?
The Family Law Act lets separated spouses agree on their rights and obligations, including property, support, parenting and any other matter in settling their affairs. A complete agreement usually covers:
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Date of separation: the key date, which fixes the valuation date for property and starting date for child and spousal support payments.
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Parenting: who has decision-making responsibility, the parenting time schedule, holidays, travel and relocation.
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Child support: each parent's income, the Guidelines (table) amount, special children’s expenses and how support is updated annually.
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Spousal support: whether support is paid, how much, for how long, and when it can be reviewed.
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Property division: each spouse's net family property and the equalization payment.
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Matrimonial home: who stays, whether it is sold or bought out, and who pays the mortgage and other expenses until then.
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Debts: who pays each debt and an indemnity if the other is pursued.
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Life insurance and benefits: life insurance to secure support obligations, and health and dental coverage for the ex-spouse and children.
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Releases: what each spouse gives up claiming in the future.
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Dispute resolution: mediation or arbitration before court if a disagreement arises later.
You do not need to settle everything at once. You can sign a partial agreement on the issues you agree on and keep working on the rest.
Can common-law partners make one?
Yes. The Family Law Act treats cohabiting partners' separation agreements the same way. Their underlying rights differ, though, especially for property. See Common-law relationships in Ontario.
When does a separation agreement hold up in court?
Ontario courts generally respect separation agreements that were properly made. An agreement is more likely to hold up when it meets the legal formalities and the process behind it was fair.
The formal requirements
A domestic contract is unenforceable unless it is made in writing, signed by the parties and witnessed. A handwritten note, an exchange of texts or an unsigned draft generally does not qualify, even if both of you meant it.
Grounds to set separation agreement aside
A court may set aside an agreement, or a single term of it, if:
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one spouse failed to disclose significant assets, debts or other liabilities that existed when it was signed;
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one spouse did not understand the nature or consequences of the agreement; or
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there is another reason under ordinary contract law, such as duress, undue influence or unconscionability.
The court still has discretion. Proving a ground does not end the agreement automatically. For a recent example, see Epshtein v. Shvartzman, 2026 ONCA 162: the Court of Appeal upheld a ruling that a pre-marriage agreement was too unclear to enforce, partly because one spouse did not understand its consequences.
Special rules for children and support
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Parenting terms. A court can disregard and override any term of the separation agreement about decision-making responsibility or parenting time that is not in the child's best interests.
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Child support. A court can disregard child support terms that are unreasonable under the Child Support Guidelines. A divorce will not be granted without reasonable child support arrangements.
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Spousal support waivers. Even a waiver can be overridden in limited situations, for example if it is unconscionable or leaves a spouse relying on public assistance. For married spouses, the Supreme Court of Canada set the test for spousal support waivers in Miglin v. Miglin, 2003 SCC 24.
What makes a separation agreement hard to challenge?
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Sworn financial statements exchanged between the parties with supporting documents.
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Independent legal advice obtained by each spouse, from separate lawyers.
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Time to consider the draft, without deadlines that create pressure.
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Clear wording that names the property and claims being settled.
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A record that the agreement is fair, or why each spouse accepts it if it departs from the law.
How is a separation agreement enforced?
You can file your agreement with the court so its support terms can be enforced like a court order, including by the Family Responsibility Office (FRO). To do this, attach the current agreement to Form 26B: Affidavit for Filing Domestic Contract or Paternity Agreement and file it, online or in person, at the Ontario Court of Justice or a Family Court branch of the Superior Court of Justice. Then register it with FRO if you want FRO to collect payments. Non-support terms, such as agreed transfer of property, are enforced through a court application if the other spouse does not comply.
Can a separation agreement be changed?
Yes, by a new written agreement signed and witnessed the same way. Without agreement, a court can change support terms when circumstances change and can revisit parenting terms if the child's best interests require it. Property terms are much harder to reopen. Changing, setting aside or enforcing a separation agreement covers each route.
Do we need a lawyer to make a separation agreement?
The law does not require one, but each spouse having independent legal advice is one of the strongest protections against a later challenge. Some couples negotiate the terms themselves or in mediation, then have a lawyer review the draft before signing. Mistakes people make with do-it-yourself separation agreements lists common gaps.
From practice
Hypothetical example. Any resemblance to a real case is coincidental.
Daniel and Elena drafted their own agreement from an online template. Elena kept the house and Daniel kept his RRSP and his share in a small company. They never exchanged financial statements, and the company was listed only by name, with no value.
Three years later, Daniel's company is sold for far more than either expected. Elena now asks whether the agreement can be reopened. The missing disclosure gives her an argument, but the outcome is uncertain and the litigation is costly for both. Had each of them exchanged sworn financial statements and taken independent advice before signing, the agreement would have been much harder to attack, and both would have known what they were giving up.
Frequently asked questions
Is a separation agreement legally binding without a lawyer? It can be, if it is in writing, signed and witnessed. Without independent legal advice, though, it is easier for a spouse to argue later that they did not understand it.
Do we need a separation agreement to be legally separated? No. You are separated once you start living separate and apart. The agreement records the terms.
Can we agree to no child support? The right to child support belongs to the child. A court can disregard child support terms that are unreasonable under the Guidelines, and will not grant a divorce without reasonable arrangements.
Who can witness the agreement? An adult who is not a party to it. Many people sign in front of their own lawyers, which also provides independent legal advice.
How long does it take to make one? It depends on how many issues are open and how quickly disclosure is exchanged. Simple agreements can take days; complex ones, months.
Talk to a family lawyer about your separation agreement
Whether you are starting from scratch or holding a draft, a free 15-minute call is a quick way to see which option fits. We can negotiate and draft the agreement, or review a draft and give independent legal advice before you sign.
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A free 15-minute phone call to talk through your situation and the next step
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By phone, by video or in person at 5200 Yonge Street, Suite 200, North York ON
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Flat fees: Independent Legal Advice on an agreement $699, or an Uncontested Separation Agreement from $1,499, plus HST
Book a free 15-minute call about your separation agreement · Call 416-858-1320
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Anton Mostovoy, lawyer, licensed by the Law Society of Ontario. Last reviewed: October 12, 2026
This page is general information about Ontario and federal law, not legal advice. Reading it or contacting us does not create a lawyer-client relationship. Laws and court fees change; check the date above.