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Cohabitation Agreement Checklist for Ontario: Documents and Disclosure

Use this Ontario checklist to gather the financial documents, assets, debts and decisions you need before signing a cohabitation agreement.

Family Law4 min readTSLBy the Treadstone Law Team · OntarioUpdated November 1, 2026
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Key takeaways
  • A cohabitation agreement must be in writing, signed by both partners and witnessed to be enforceable.
  • A court may set an agreement aside if a party failed to disclose significant assets, debts or other liabilities that existed when it was made.
  • Ontario's guidance advises that partners speak to different lawyers and exchange financial information before signing.

Most of the work in a cohabitation agreement happens before anyone signs. Putting together a clear picture of what each of you owns and owes makes the conversation easier and makes the agreement stronger.

This checklist covers the documents, assets, debts and decisions couples commonly gather. It is a general guide, and a lawyer can tell you what matters for your situation.

Why disclosure matters

Two unmarried people who are cohabiting or intend to cohabit can make a cohabitation agreement covering property, support and other matters in settling their affairs. Without one, unmarried partners are generally not legally required to split property acquired while living together, and household items belong to the person who bought them.

If you want a different result, the agreement has to say so, and it has to be reliable. A court may set aside a domestic contract if a party failed to disclose significant assets, debts or other liabilities that existed when it was made. Full disclosure protects both of you.

Financial documents to gather

Each partner should collect their own records. Typical items include:

Exact lists vary with your circumstances, so ask your lawyer what else is relevant.

Assets and debts to sort out

Go through what each of you brings into the relationship and what you expect to acquire together. Questions worth answering in writing:

Decisions about support, children and the future

Many couples also decide how they will deal with support if they separate. Unmarried partners can be spouses for support if they have cohabited continuously for at least three years, or have a child together and a relationship of some permanence. An agreement can address support, but a court may set aside a support waiver where it results in unconscionable circumstances, where the dependant qualifies for support from public money, or where support is in default.

Children need separate attention. A cohabitation agreement cannot fix decision-making responsibility or parenting time. A court may also disregard a child support term that is unreasonable under the child support guidelines, and may disregard education or parenting terms where that is in the child's best interests.

Finally, think about marriage. If the parties to a cohabitation agreement marry each other, it is deemed to be a marriage contract.

Signing properly and next steps

The agreement, and any later change to it, is unenforceable unless it is in writing, signed by the parties and witnessed. Ontario's guidance advises that you speak to different lawyers and exchange financial information before signing. A court can also set aside a contract if a party did not understand its nature or consequences.

Frequently asked questions

Do we both need our own lawyer for a cohabitation agreement?

The formal signing rules require writing, signatures and a witness, and do not list independent legal advice as a requirement. Ontario's guidance still advises speaking to different lawyers, and advice helps show each person understood the agreement, which is one ground for setting one aside.

What happens if my partner left out an asset?

A court may set the agreement, or part of it, aside if a party failed to disclose significant assets, debts or other liabilities that existed when it was made. Whether that applies depends on the facts, so speak with a lawyer.

Can the agreement decide parenting time?

No. A cohabitation agreement cannot fix decision-making responsibility or parenting time for children.

Is a cohabitation agreement valid if only one of us signs?

No. It is unenforceable unless it is in writing, signed by the parties and witnessed.

Sources

Links go to official government, court and regulator pages. The law changes — confirm you are reading the current version.

This article is general information, not legal advice. Reading it does not create a lawyer-client relationship. Ontario laws, tax rates, and government programs change, and how the law applies depends on your specific facts. For advice about your situation, speak with a licensed Ontario lawyer. Treadstone Law is licensed by the Law Society of Ontario — reach us at 1-844-900-1070 or start a file online.

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