A negligence claim in Ontario requires proving four elements on a balance of probabilities: the defendant owed you a duty of care, they breached the standard of a reasonable person in the same circumstances, that breach caused your loss, and you suffered actual, compensable damages. Claims can arise from business, professional, or property-related conduct, not only personal injury.
- Negligence requires proving all four elements: duty of care, breach, causation, and damages.
- Duty of care is the threshold question — it must be established before the other elements are even considered.
- The standard is what a reasonable person would have done in the same circumstances, not perfection.
- Causation is often the most contested element — you must show the breach actually caused your loss, and that the loss was not too remote.
- Negligence claims are not limited to personal injury; they can arise from professional, business, and property-related conduct.
- You generally have two years from discovering your loss to bring a negligence claim.
The Four Elements of Negligence
A negligence claim in Ontario requires proving four distinct elements, each on a balance of probabilities: duty of care, breach of the standard of care, causation, and damages. Missing any one of these elements is fatal to the claim, regardless of how clearly the others are established.
Duty of Care
Duty of care is the gateway question — courts ask whether the law recognizes an obligation between the parties given their relationship and the foreseeability of harm. Some duties are well established (drivers to other road users, professionals to their clients, property owners to visitors); others require a more detailed legal analysis of the specific relationship and circumstances.
Breach of the Standard of Care
Once a duty exists, the question becomes whether it was breached — measured against what a reasonably prudent person would have done in the same circumstances. This is not a standard of perfection. Professionals, such as contractors, accountants, or other service providers, are generally held to the standard of a reasonably competent member of their profession, not an idealized expert.
Something going wrong does not, by itself, prove negligence. The question is always whether the defendant's conduct fell below what a reasonable person in their position would have done.
Causation
Causation is frequently the most contested element of a negligence claim. Courts typically apply a "but for" test — would the harm have occurred but for the defendant's breach? Even where factual causation is established, the defendant is only liable for damages that were reasonably foreseeable and not too remote a consequence of the breach.
When several factors could explain a loss, isolating the defendant's specific contribution can require expert evidence — engineering, accounting, or industry-specific opinion — to meet your burden of proof.
Damages
Finally, you must prove actual, compensable harm — not simply that a mistake occurred. Recoverable damages vary with the type of claim, but can include direct financial losses, the cost of remedying the harm, and, in personal injury matters, medical expenses, lost income, and pain and suffering.
A Toronto business relies on a contractor's faulty electrical work, which later causes a fire and significant property loss. Proving negligence requires showing the contractor owed a duty of care, fell below the standard expected of a reasonably competent electrician, that this specific failure caused the fire (not some unrelated cause), and quantifying the resulting loss.
Common Types of Negligence Claims
- Professional negligence — advisors, contractors, and other service providers who fall below the expected standard
- Property-related negligence — unsafe conditions causing injury or loss
- Business negligence — carelessness by a supplier or service provider causing financial loss
Negligence claims often overlap with, or are pleaded alongside, a related breach of contract claim where a contractual relationship exists between the parties.
Building Your Case
We start by identifying the specific duty owed, gathering the evidence needed to show the standard of care was breached, and — where causation is contested — working with the right experts to connect the breach to your actual loss. A clear-eyed assessment of causation early on avoids investing in a claim that cannot ultimately be proven.
Call our Toronto negligence lawyers at 416-274-2222 to discuss your potential claim.
Frequently Asked Questions
Duty of care, breach of the standard of care, causation, and damages. All four must be proven on a balance of probabilities — meaning it is more likely than not that each element is present — or the claim fails.
A duty of care exists where the law recognizes that one party must act as a reasonable person would toward another, given their relationship and the foreseeability of harm. It is a threshold legal question decided before the court looks at whether that duty was actually breached.
Courts ask whether the defendant acted as a reasonably prudent person would have in the same circumstances — not whether they acted perfectly. Professionals are generally held to the standard of a reasonably competent member of their profession.
You must show that "but for" the defendant's breach, your loss would not have occurred, and that the loss was a reasonably foreseeable consequence of the breach. Where multiple factors contributed to a loss, isolating the defendant's specific contribution can be genuinely difficult and often requires expert evidence.
Recoverable damages depend on the nature of the claim, but can include direct financial losses, costs to remedy the harm, and in personal injury matters, medical expenses, lost income, and pain and suffering. You must show actual, provable harm — not just that a mistake was made.
No. Negligence principles apply broadly — to professional negligence, property damage, business losses caused by a service provider's carelessness, and more. Personal injury is simply the most well-known category.
Generally two years from when you discovered, or reasonably ought to have discovered, the loss and that it was caused by the defendant's conduct — subject to Ontario's ultimate 15-year limitation period.