Breach of Contract in Ontario: Rights, Remedies and Next Steps

A breach of contract happens when a party to an agreement fails, without a lawful excuse, to do what they promised to do. That sounds simple, but in practice it covers a wide range of situations: a supplier that delivers goods weeks late, a contractor who walks off a renovation halfway through, a client who stops paying invoices, or a business that quietly stops honouring an exclusivity clause it agreed to.

The starting point for any breach analysis is the contract itself. Ontario courts look first at what the parties actually agreed to — the written terms if there’s a signed agreement, or the best available evidence of what was promised if the arrangement was verbal. From there, the question becomes whether what actually happened lines up with what was promised, and if not, how far off it was.

It’s worth noting that not every disappointment is a breach. If a contract gives a party discretion to make a certain decision, or includes a clause excusing performance in specific circumstances (sometimes called a force majeure clause), conduct that looks like a broken promise on the surface might still be within the four corners of what was agreed. This is one reason a careful read of the actual contract language matters more than a gut sense that something feels unfair.

Not all breaches are treated the same way, and the label matters because it affects what a non-breaching party is entitled to do in response.

Minor breach. A minor, or partial, breach is a small deviation from what was promised that doesn’t defeat the overall purpose of the contract. A short, inconsequential delay in an otherwise complete delivery is a common example. A minor breach may still cause a compensable loss, but it generally doesn’t excuse the other side from continuing to perform its own obligations under the contract.

Material breach. A material breach is significant enough that it goes to the heart of the agreement. When a material breach occurs, the non-breaching party may be entitled to treat the contract as at an end and stop performing its own remaining obligations, in addition to pursuing damages for the loss caused.

Fundamental breach. This is a breach so severe that it effectively defeats the entire purpose of the contract. The concept can also affect whether certain limitation of liability or exclusion clauses continue to apply, since some clauses are drafted (or interpreted) not to protect a party from the consequences of a fundamental failure to perform.

Anticipatory breach. Sometimes a party makes clear, before performance is even due, that it doesn’t intend to honour the agreement — cancelling an order months in advance, for instance, or explicitly refusing to close a deal. Ontario law generally allows the other party to treat this as an immediate breach rather than waiting for the performance date to arrive and pass.

Breach of contract disputes turn up across almost every kind of agreement, but certain patterns come up again and again in Ontario. A missed or late payment is probably the most common trigger — whether that’s a client who stops paying invoices, a tenant who stops paying rent, or a business that skips an instalment on a payment plan. Work not completed to the agreed standard is another frequent source of disputes, particularly in construction, renovation, and professional services relationships where “good enough” is subjective until it’s written down clearly.

Other common examples include goods delivered late, short, or not at all; a party using confidential information in a way a non-disclosure agreement was meant to prevent; one side ending an ongoing agreement without giving the notice the contract required; and a business breaching a non-compete or exclusivity clause it agreed to when the relationship started. Lease-related breaches — on both the landlord and tenant side — are common enough that they’re covered in more depth in our lease agreements hub and commercial lease insights.

Business relationships add their own recurring patterns on top of these: a partner who stops contributing agreed capital or effort, a contractor engaged as “independent” who is treated more like an employee without the contract ever being updated, or a vendor that unilaterally changes pricing or delivery terms mid-contract. In each case, the same basic questions apply — what was promised, what happened instead, and how much that gap actually cost.

If you’re on the receiving end of a breach, your rights generally flow from three sources: the specific terms of the contract itself, the general principles of Ontario contract law, and — in some relationships, like landlord-tenant or employment — specific legislation that layers additional protections on top of the contract.

As a starting point, you’re generally entitled to expect the other party to either fix the problem, compensate you for the loss it caused, or both, depending on the severity of the breach and what the contract says about remedies. You may also have the right to withhold your own performance in response to a material breach by the other side — for example, declining to pay for work that wasn’t completed as promised — though this is an area where getting the analysis wrong can expose you to a counterclaim, so it’s worth being cautious before treating a contract as over.

You’re also generally entitled to document the breach, request specific information about what happened and why, and set a reasonable deadline for the other party to respond or fix the problem before you escalate. This is usually done through a formal demand letter, which puts the dispute on the record and often resolves the matter without anything further being necessary.

The most common remedy for breach of contract in Ontario is damages — financial compensation intended to put the non-breaching party in the position they would have been in had the contract been performed as promised. This is often called an expectation measure of loss, and it’s the default a court will consider in most commercial disputes.

Other remedies exist alongside or instead of damages in narrower circumstances. A court can sometimes order specific performance, requiring a party to actually carry out its obligations — this tends to be reserved for situations involving something unique, like a specific piece of real estate or a rare item, where money alone wouldn’t fairly compensate the loss. Rescission allows a contract to be unwound entirely in certain circumstances, effectively cancelling it and returning both parties to their position before the agreement was made. And in some cases, a party can pursue restitution, recovering a benefit unfairly retained by the other side.

Whatever remedy is being pursued, the person claiming a loss is generally expected to take reasonable steps to mitigate, or limit, that loss. A business that loses a supplier partway through a contract, for example, is usually expected to make a reasonable effort to find a replacement rather than simply letting losses accumulate and claiming the full amount later.

Many contracts also try to define remedies in advance. A liquidated damages clause sets a pre-agreed amount payable if a specific breach occurs, which can simplify disputes considerably — though courts will scrutinize a clause that looks more like a penalty than a genuine pre-estimate of loss. A limitation of liability clause caps what one party can recover from the other, and is common in service and technology agreements. These clauses are generally enforceable in Ontario if they’re clearly worded and weren’t buried or misrepresented at signing, which is one more reason it’s worth reading a contract’s remedies section closely before a dispute arises, not after.

If you believe a contract has been breached, the most useful first step is usually to gather your documentation: the agreement itself (or your best record of what was verbally agreed), any related emails, texts, or invoices, and a clear record of the loss the breach has caused you. This documentation shapes every decision that follows, including whether a claim is worth pursuing and how strong it’s likely to be.

From there, many disputes move through a fairly predictable sequence: a direct conversation or written request to fix the problem, followed by a formal demand letter if that doesn’t resolve things, followed by mediation, arbitration, or a court claim if the demand goes unanswered. You can read more about each of those paths in our guide to demand letters and our overview of dispute resolution options.

It’s also worth checking Ontario’s limitation period for contract claims early on. Ontario generally applies a two-year limitation period to many contract claims, and waiting too long to act can permanently affect your ability to pursue a claim — even a strong one — so it’s worth confirming the applicable deadline as soon as a breach becomes apparent.

Finally, think about proportionality. Litigation isn’t free, and even a valid claim can cost more in time and legal fees than it ultimately recovers if the amount at stake is small. For smaller claims, Ontario’s Small Claims Court is designed to be a more accessible venue, while larger or more complex disputes are generally better suited to the Superior Court of Justice. Weighing the size of the loss against the cost and time of each option is a normal, practical part of deciding what to do next — not a sign that a claim isn’t worth pursuing.