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Unjust Enrichment vs. Joint Family Venture in Ontario: What’s the Difference?

Unjust enrichment and joint family venture are related but different claims for Ontario common-law partners. Here’s how they compare and which may fit.

Family Law5 min readTSLBy the Treadstone Law team · OntarioUpdated 2026-07
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Key takeaways
  • Unjust enrichment is a broad legal doctrine that isn’t unique to family or relationship situations at all — it applies any time one party has been enriched at another’s expense, with no…
  • A joint family venture claim isn’t a completely separate legal doctrine — it’s a specific way courts have applied unjust enrichment principles within long-term domestic relationships…

If you’ve started researching what happens to property when a common-law relationship ends in Ontario, you’ve probably run into both "unjust enrichment" and "joint family venture." The two terms are closely related, often discussed together, and easy to confuse. They aren’t the same thing.

This article breaks down what each one means, how they differ, and how they tend to work together in practice.

Unjust Enrichment: The General Framework

Unjust enrichment is a broad legal doctrine that isn’t unique to family or relationship situations at all — it applies any time one party has been enriched at another’s expense, with no legal justification for keeping the benefit.

The general framework asks three questions:

  1. Was one party enriched?
  2. Did that enrichment come at a corresponding deprivation to the other party?
  3. Is there any juristic reason — a contract, a valid gift, a legal obligation, or some other lawful basis — explaining why the enriched party should be allowed to keep the benefit?

If the answer to the third question is no, a court can order a remedy. In many unjust enrichment cases outside family situations, that remedy is simply monetary compensation reflecting the value of what was contributed.

Joint Family Venture: A More Specific Application

A joint family venture claim isn’t a completely separate legal doctrine — it’s a specific way courts have applied unjust enrichment principles within long-term domestic relationships where the couple’s efforts and resources were genuinely pooled toward common family goals, functioning more like a single economic unit than two separate individuals.

Rather than trying to value each individual task or contribution separately, a joint family venture approach lets a court consider the relationship as a whole and, where appropriate, award a share of the wealth accumulated during the relationship — proportionate to each partner’s overall contribution to the joint effort.

How the Two Compare

Unjust Enrichment (general)Joint Family Venture
Applies toAny relationship or transaction, not just couplesLong-term domestic relationships functioning as an economic partnership
FocusA specific enrichment and deprivation tied to identifiable contributionsThe overall pooling of effort and resources toward common goals
Typical remedy approachCompensation reflecting the value of the specific contribution or serviceA proportionate share of the wealth accumulated during the relationship
What you generally need to showEnrichment, a corresponding deprivation, and no juristic reason for itThe same elements, plus evidence of a genuine joint venture — integration, mutual effort, and common goals

Which One Might Apply to You

Think of joint family venture less as a rival claim and more as a specific lens a court can apply to unjust enrichment within the right kind of long-term relationship. Many common-law property cases raise both — the unjust enrichment framework as the underlying legal foundation, and the joint family venture approach as the argument for a proportionate share of accumulated wealth rather than a narrower value-for-services calculation.

Which framing fits your situation best depends heavily on your specific facts: how long the relationship lasted, how integrated your finances were, and whether your contributions were tied to one specific asset or to the couple’s overall financial life together. This is exactly the kind of assessment worth getting from a family lawyer rather than guessing at from general information.

Frequently asked questions

Can I bring both an unjust enrichment claim and a joint family venture claim at once?

Yes. They’re often pleaded together, since joint family venture is really a specific application of unjust enrichment principles rather than a fully separate cause of action.

Do I need to have lived together a certain number of years to make a joint family venture claim?

There’s no fixed minimum length that guarantees success. What matters more is the degree of financial and practical integration during the relationship, not simply how long it lasted.

Does marriage change which claim applies?

Married spouses generally rely on the Family Law Act’s equalization scheme rather than unjust enrichment or joint family venture claims, since equalization already provides a statutory sharing right common-law partners don’t have. These doctrines are most relevant where no such statutory right exists.

What kind of remedy could I actually receive?

It depends on how your claim is framed and proven — outcomes can range from monetary compensation reflecting specific contributions to a proportionate interest in accumulated wealth under a joint family venture approach. There’s no fixed formula, so speak with a lawyer about what’s realistic on your facts.

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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