What Is Equity? The Doctrine That Lets Canadian Courts Do What’s Fair

If you have ever read a contract dispute in the news where a court ordered a seller to actually transfer the property they agreed to sell, rather than just pay damages, you have seen equity at work. If you have heard of a court ordering a noisy factory to stop polluting at midnight on a court order, you have seen equity. If you have read about a person who took advantage of a vulnerable elderly relative being forced to give back the house, even though every signature on every document was technically valid, you have seen equity.

Equity is one of the most fascinating and least-understood areas of Canadian law. It is the body of doctrine that gives courts the power to do what is fair, in cases where the strict rules of the common law would produce a result that almost everyone would recognize as unjust. It is the reason a Canadian court can intervene in transactions and relationships and say, in effect: “the technical legal position is one thing, but conscience requires something else.”

This article is a tour of equity for the general reader. It explains where equity came from, how it differs from the ordinary common law, the famous “maxims” that judges still recite to guide their reasoning, and the principal remedies that equity makes available, including specific performance, injunctions, rescission, rectification, relief against forfeiture, and the constructive trust. It is written for anyone curious about how Canadian law actually works, for parties facing a dispute that may involve equitable claims or remedies, and for lawyers who want a refresher on the architecture of equitable jurisdiction. Our commercial litigation practice and unjust enrichment practice regularly handle disputes that turn on equitable principles in Ontario.

Where Equity Came From: A Brief History

To understand equity, you have to understand a strange feature of medieval English law. By the fourteenth century, the English common law had developed into a sophisticated but rigid system. The royal courts (King’s Bench, Common Pleas, and Exchequer) decided cases by applying fixed rules and standardized “writs” that channelled disputes into pre-set categories. If your case did not fit a writ, you had no claim. If your case fit a writ but the strict application of the rules produced an absurd result, the courts had no flexibility to do otherwise.

People who could not get justice in the common law courts began petitioning the King directly. The King, in his role as the “fount of justice,” referred these petitions to his Chancellor, who was both the senior royal official and (in the early period) typically a clergyman. The Chancellor’s role was to decide each case according to “conscience,” meaning a sense of moral fairness, rather than according to the technicalities of the common law writs. Over time, this practice solidified into a separate court system, the Court of Chancery, with its own procedures, its own remedies, and its own body of doctrine. This was the birthplace of equity.

For several centuries, England operated with two parallel court systems: the common law courts on one hand, and the Court of Chancery (the equity court) on the other. Each had its own jurisdiction, its own rules, and its own remedies. A litigant might need to bring proceedings in both courts to get full relief. The system was cumbersome, expensive, and full of opportunities for tactical games.

In the nineteenth century, both England and the Canadian provinces enacted “Judicature Acts” that fused the two systems. After fusion, the same courts could administer both common law and equitable principles, and a litigant could obtain both types of relief in a single proceeding. But the doctrines remained distinct. A claim in equity is still analyzed using equitable principles; an equitable remedy is still a remedy of equity. As one English judge put it, “the waters of the confluent streams of law and equity have surely mingled now,” but the streams retain their character even after they meet.

In Canada, the provincial superior courts (the Ontario Superior Court of Justice and its equivalents in other provinces) administer both common law and equity, and equity prevails where the two conflict. The Ontario Superior Court of Justice draws its general jurisdiction from section 96 of the Constitution Act, 1867, and the modern administration of equitable jurisdiction in Ontario is governed by the Courts of Justice Act. The Federal Court has similar concurrent jurisdiction. Equity is therefore not a separate body of law to be invoked in a separate court; it is part of the everyday work of every superior court trial judge in Canada.

What Makes Equity Different

The most important thing to understand about equity is that it is fundamentally discretionary. Where the common law deals in rights, equity deals in conscience. Where the common law generally awards a remedy as of right when liability is established, equity awards remedies as a matter of judicial discretion, taking into account the conduct of both parties and the overall fairness of the result.

This means that even a person with a strong legal claim may be denied an equitable remedy if their conduct is found wanting, if they have delayed too long in pursuing their rights, or if granting the remedy would produce a result that is itself unjust. By the same token, a person whose strict legal position is weak may obtain equitable relief if the conscience of the court is engaged by the conduct of the other party.

The classic illustration involves the sale of a unique piece of property. Suppose a seller agrees to sell a particular antique painting to a buyer, but then changes their mind and refuses to deliver it. At common law, the buyer’s remedy would be damages: they could sue for the difference between the contract price and the market price of the painting. But damages are a poor substitute for the painting itself, which is unique and cannot be replaced. Equity steps in with the remedy of “specific performance,” which is an order requiring the seller to actually deliver the painting as agreed. The remedy is discretionary: the court will grant it only if it is satisfied that damages are inadequate, that the seller’s conduct is unconscionable, that the buyer has acted promptly, and that the result is fair. But where those conditions are met, equity gives the buyer something that the common law alone could not.

The Maxims of Equity

Over the centuries, judges and writers have distilled the principles of equity into a set of “maxims,” which are short pithy statements that encapsulate how equity reasons. The maxims are not strict rules; they are guidelines, and they sometimes appear to conflict with each other. But they are the vocabulary in which equitable reasoning is conducted, and they remain in active use in Canadian courts.

The Supreme Court of Canada in Cadbury Schweppes Inc. v. FBI Foods Ltd. emphasized that the maxims of equity are not rigid rules but malleable principles intended to serve the ends of fairness and justice. They are background guideposts, not algorithms.

“Equity Will Not Suffer a Wrong to Be Without a Remedy”

This maxim expresses the foundational ambition of equity: where the common law fails to provide a remedy for a genuine wrong, equity will fill the gap. It is so general that it cannot be applied directly to particular cases (almost every plaintiff says they have suffered a wrong), but it animates the whole of equitable jurisdiction. It is the maxim that explains why equity invented specific performance, injunctions, the constructive trust, rescission, rectification, and the other remedies discussed in this article.

“Equity Follows the Law”

Equity does not casually override the common law. Where the common law produces an answer that is broadly fair, equity follows it. Equity intervenes only where the common law’s answer is genuinely unconscionable, where it ignores the substance of what was intended, or where it leaves a wrong without a remedy. This maxim is a constraint on equitable creativity; it reminds judges that equity is supplemental to law, not a free-floating jurisdiction to do whatever feels right.

“He Who Seeks Equity Must Do Equity”

A person who asks for equitable relief must themselves be willing to act fairly. A buyer suing for specific performance must be ready to pay the purchase price. A party seeking rescission of a contract must be ready to restore what they have received under it. The maxim recognizes that equitable relief is a form of cooperation between the court and the litigant, and the litigant must do their part.

“He Who Comes to Equity Must Come With Clean Hands”

The “clean hands” doctrine is one of the most distinctive features of equity. A person who has acted improperly in connection with the matter before the court may be denied equitable relief, even if their underlying claim has merit. The wrongdoing must be related to the matter in dispute, not merely a general flaw in the plaintiff’s character. But where the plaintiff’s misconduct is sufficiently connected to the equitable claim, the court can refuse relief on this ground alone.

This is one of the reasons equity feels different from the common law. A common law plaintiff who establishes their claim is entitled to damages even if they have behaved badly in unrelated ways. An equity plaintiff can be sent away empty-handed because the court is not satisfied that they themselves have acted with integrity in connection with the dispute.

“Delay Defeats Equity” (the Doctrine of Laches)

A person seeking equitable relief must act promptly. Where a plaintiff delays unreasonably in asserting their equitable claim, and the delay has prejudiced the defendant, the court may refuse relief on the ground of “laches.” Laches is distinct from a statutory limitation period. A statutory limitation period is a fixed time bar; laches is a discretionary doctrine that depends on the facts of the case, including the length of the delay, the reasons for it, and any prejudice it has caused. Even where a claim is technically within the limitation period, laches can defeat it if the equitable conscience of the court is engaged by the plaintiff’s lack of vigilance.

“Equity Looks to the Intent Rather Than the Form”

Equity will not let a defendant escape liability by hiding behind the formal label or structure of a transaction when the substance of what was intended was different. If the parties intended a transaction to be a security interest but documented it as a sale, equity may treat it as a security interest. If the parties intended one document to capture their agreement but signed another by mistake, equity may rectify the document to reflect the true agreement. This maxim is the basis of much of modern commercial equity, including the constructive trust, rectification, and the analysis of nominal versus beneficial ownership.

“Equity Looks On That as Done Which Ought to Be Done”

When the parties have agreed that something is to be done, and it could and should have been done, equity may treat it as if it has already been done for the purposes of analyzing rights between the parties. This maxim is the foundation of important doctrines including the equitable assignment, the doctrine of conversion (treating land contracted to be sold as if already converted to money), and the modern law of constructive trusts arising from agreements for sale.

“Equity Acts In Personam”

Traditionally, equity acted on the conscience of the defendant personally, rather than on the property in question directly. An order for specific performance is an order to the defendant to perform; if the defendant refuses, they are in contempt of court. This is different from a common law judgment, which becomes a debt that can be enforced by seizure of assets or other “in rem” mechanisms. The “in personam” character of equity has important consequences for jurisdiction (a Canadian court can sometimes order a defendant within its jurisdiction to do something with respect to property outside the jurisdiction, because the order acts on the defendant rather than on the foreign property).

The Principal Equitable Remedies

Equity’s contribution to modern Canadian law is most visible in the remedies it makes available. These remedies sit alongside common law damages and (in many cases) provide forms of relief that the common law alone could never have achieved.

Specific Performance

Specific performance is an order requiring a party to perform their contractual obligation. It is most commonly ordered in contracts for the sale of land (each piece of land was traditionally regarded as unique, so damages were always inadequate) and in other contracts where the subject matter is genuinely unique. The court will not order specific performance where damages are an adequate remedy, where the contract is uncertain, where performance would require constant judicial supervision (as in personal service contracts), or where the result would be unjust. In recent decades, Canadian courts have become more cautious about ordering specific performance even in land cases, requiring the plaintiff to show that the property has some genuinely unique quality that makes damages inadequate.

Injunctions

An injunction is a court order requiring a person to do something (a “mandatory” injunction) or, more commonly, requiring a person not to do something (a “prohibitive” injunction). Injunctions can be permanent (granted as a final remedy after trial), interlocutory (granted pending trial), or interim (granted very briefly until the parties can be heard). The classic test for an interlocutory injunction in Canada is the three-part test from RJR-MacDonald Inc. v. Canada (Attorney General): there must be a serious issue to be tried, irreparable harm if the injunction is not granted, and the balance of convenience must favour granting the injunction.

Injunctions are routinely sought in commercial litigation to prevent the dissipation of assets pending trial (a “Mareva injunction”), to prevent the use or disclosure of confidential information, to prevent breaches of restrictive covenants by departing employees, to stop nuisance or trespass, and in many other contexts. The injunction is one of the most powerful tools available to a litigant, and its discretionary nature gives courts significant latitude to fashion the order to fit the circumstances of the case.

Rescission

Rescission is the equitable remedy of unwinding a contract. Where a contract has been induced by misrepresentation, mistake, undue influence, or unconscionable conduct, equity allows the innocent party to set the contract aside and to be restored to the position they were in before the contract was made. Rescission is “ab initio” (from the beginning), meaning that the contract is treated as if it had never existed.

Rescission is subject to several limits. The plaintiff must act promptly (delay can bar the remedy). The parties must be capable of being restored substantially to their pre-contractual positions (if too much has changed, rescission may be impossible). And the rights of innocent third parties who have acquired interests in good faith may bar rescission. But where these conditions are met, rescission is a powerful remedy that allows a victim of unfair dealing to escape the contract entirely.

Rectification

Rectification is the equitable remedy of correcting a written document to reflect what the parties actually agreed. It is available where there is clear evidence that the written document does not capture the true agreement of the parties, typically because of a drafting error or mutual misunderstanding. Rectification does not change the agreement; it changes the document to match the agreement. The Supreme Court of Canada has emphasized that rectification is a narrow remedy: it requires clear and convincing evidence of the prior agreement and of the discrepancy between that agreement and the written document. It is not a tool to renegotiate a deal that one party has come to regret.

Relief Against Forfeiture

Where a contract or lease provides that one party will lose a right (typically a property right) if they default, equity can in some cases relieve the defaulting party from the forfeiture and allow them to retain the right by curing the default. Relief against forfeiture is most commonly seen in commercial leases (where a tenant who has fallen behind on rent or breached a covenant may, in appropriate circumstances, be relieved from termination of the lease) and in instalment land contracts (where a purchaser who has paid much of the price and then defaulted may, in appropriate circumstances, be relieved from forfeiture of the partial payments). The court considers the conduct of the parties, the seriousness of the default, the value at stake, and whether the defaulting party can be put back in good standing.

The Constructive Trust

The constructive trust is one of equity’s most powerful and flexible remedies. Where a defendant holds property in circumstances that would make it unconscionable for them to retain the beneficial interest, the court can declare that the defendant holds the property on a “constructive trust” for the plaintiff, who acquires an equitable interest in the property. The constructive trust converts the defendant from owner to trustee, with all the fiduciary obligations that role entails.

The Supreme Court of Canada in Soulos v. Korkontzilas set out the modern framework for constructive trusts arising from breach of fiduciary duty or other wrongful acquisition of property. In Pettkus v. Becker, the court extended the constructive trust to cases of unjust enrichment, where the plaintiff’s contributions have unjustly benefited the defendant and there is no juristic reason for the defendant to retain the benefit. The decision in Kerr v. Baranow developed the modern law on choice of remedy in unjust enrichment cases involving domestic relationships. The constructive trust is particularly powerful because it is a proprietary remedy: the plaintiff acquires an equitable interest in identifiable property, with priority over the defendant’s general creditors in insolvency.

Equitable Damages

Equity also provides for damages in some circumstances, either in addition to or in substitution for other equitable remedies. Equitable damages are particularly important in cases where specific performance or an injunction is sought but, for one reason or another, is not granted. The court can order equitable damages instead, calculated to compensate the plaintiff for the loss they have suffered. Equitable damages are also available for breach of fiduciary duty and for breach of certain equitable doctrines that have no common-law analog.

Why Equity Matters in Modern Disputes

Equity is not a historical curiosity. It is integral to many of the most important areas of modern Canadian commercial and personal law.

Real Estate

Almost every land transaction in Canada is governed in part by equitable principles. The agreement of purchase and sale creates an equitable interest in the buyer (under the maxim “equity looks on that as done which ought to be done”) even before closing. Specific performance is available for breach. Constructive trusts arise where a party fails to carry through with an agreed transaction. Rectification corrects errors in conveyancing documents. Relief against forfeiture protects defaulting purchasers in instalment contracts.

Family Property and Domestic Relationships

The doctrine of unjust enrichment, as developed in Pettkus v. Becker and Kerr v. Baranow, governs the financial consequences of common-law (unmarried) relationships in Canada. Where one partner has contributed to the accumulation of wealth held in the other’s name, the constructive trust and monetary unjust enrichment remedies provide a way to do justice between the parties. Without equity, common-law spouses would have no claim against each other on separation, regardless of the contributions they had made to the relationship.

Commercial Litigation

Equity is the source of many of the most powerful tools in commercial litigation: injunctions to preserve assets and prevent harm, specific performance to enforce unique contracts, rescission for misrepresentation, rectification of mistaken documents, constructive trusts for breach of fiduciary duty and for proceeds of fraud, and the equitable doctrine of laches as a defence to stale claims. Sophisticated commercial litigators routinely plead equitable claims alongside common law claims to ensure that all available remedies are on the table.

Trusts and Fiduciary Relationships

The whole of trust law is a creation of equity, and trusts are fundamental to modern Canadian commercial and personal life: pension trusts, investment trusts (mutual funds, ETFs), testamentary trusts (under wills), inter vivos trusts (used in estate planning, asset protection, and tax planning), and the implied trusts (resulting and constructive) that arise in litigation. Fiduciary duties, which govern the relationships between trustees and beneficiaries, lawyers and clients, agents and principals, partners and partnerships, and corporate directors and the corporations they serve, are also a creation of equity.

Restitution and Unjust Enrichment

The doctrine of unjust enrichment is the equitable response to situations where one party has been enriched at another’s expense in circumstances where there is no legal basis for the enrichment. The remedies include restitutionary damages and (where appropriate) a constructive trust. The doctrine has applications in contract disputes (recovery of payments made under contracts that have failed), tort (recovery of profits earned through wrongful conduct), and a wide range of other contexts.

Equity in Practice: A Hypothetical

Consider a hypothetical that pulls together several of the doctrines discussed above. A small business owner, anxious to expand, signs an agreement to buy a unique commercial property at a price set by the seller. The agreement is documented hastily and contains a drafting error: the legal description omits a strip of land that is essential for vehicle access to the property. The seller, realizing they could get a higher price elsewhere, refuses to close and offers to return the deposit.

Common law alone would offer the buyer little. The agreement, on its face, does not include the access strip. Damages might be awarded for breach of the agreement as drafted, but the buyer’s real loss is the loss of the property, not the loss of an inferior version of it.

Equity changes the picture. The buyer can seek specific performance of the agreement, on the basis that the property is unique and damages are inadequate. The buyer can also seek rectification of the agreement to include the access strip, on the basis of clear evidence that both parties intended to include it but the document was drafted in error. Once the agreement is rectified, specific performance can be ordered to require the seller to convey the property as the parties actually agreed. The buyer can also seek an interlocutory injunction to prevent the seller from selling the property to anyone else pending the outcome of the litigation. And if the seller has acted with bad faith, the buyer can argue that the seller is not entitled to any equitable defences (because they do not come with clean hands).

This is what equity does. It allows the court to look at the substance of what was intended, to fashion a remedy that fits the actual loss, and to refuse to let a defendant escape on a technicality. It is not unlimited, and it is not a licence to do whatever feels right. But within its scope, it is one of the most distinctive and powerful features of the common-law tradition.

Conclusion

Equity is the conscience of the common law. It is the body of doctrine that allows courts to look beyond the formal legal position and ask whether the result is fair. It is the source of many of the most distinctive features of Canadian law, including specific performance, injunctions, constructive trusts, the doctrine of unjust enrichment, fiduciary duties, and the law of trusts. Its maxims, developed over centuries, remain in active use in Canadian courts as guideposts to fair and principled decision-making.

For the general reader, the most important thing to take away from this overview is that Canadian law is not just about strict rules and entitlements. Where the rules would produce an unjust result, where one party has acted unconscionably, where the substance of what was intended has been buried under technicalities, equity can intervene. It is one of the deepest and most important features of the common-law tradition, and it remains as relevant today as it was in the courts of medieval Chancery.