One of the most common questions people ask after being charged with assault is: “But I was defending myself—isn’t that legal?” The answer is yes, self-defence is a complete defence to assault charges in Canada. However, the law surrounding self-defence is nuanced, and successfully raising this defence requires understanding what the law permits and prohibits.
The Legal Framework: Section 34 of the Criminal Code
Canada’s self-defence law is found in Section 34 of the Criminal Code, which was significantly reformed in 2012 to simplify and clarify the law.
Section 34(1) states:
A person is not guilty of an offence if:
- They believe on reasonable grounds that force is being used or threatened against them or another person
- The act constituting the offence is committed for the purpose of defending themselves or another person from that use or threat of force
- The act committed is reasonable in the circumstances
This three-part test is the foundation of every self-defence claim in Canada.
Breaking Down the Self-Defence Test
1. Reasonable Belief of Threat
You must have believed, on reasonable grounds, that force was being used or threatened against you.
Key points:
- The belief must be honest AND reasonable
- You don’t need to be correct—you just need reasonable grounds for your belief
- The threat can be force or the threat of force
- You can defend another person, not just yourself
Example: If someone aggressively approaches you with their fist raised and threatens to hit you, you have reasonable grounds to believe force is about to be used, even if they never actually swing.
2. Defensive Purpose
You must have acted for the purpose of defending yourself (or another person) from the use or threat of force.
This means:
- Your motivation was defensive, not retaliatory
- You weren’t seeking revenge or punishment
- You were trying to protect yourself or someone else
The problem with retaliation: If someone hits you, you defend yourself, and then—once the threat has ended—you continue hitting them, the continued force is no longer defensive. It becomes retaliation, which is not protected by self-defence law.
3. Reasonable Force in the Circumstances
This is often the most contentious element. The force you used must have been reasonable in the circumstances.
Section 34(2) lists factors courts consider when assessing reasonableness:
- The nature of the force or threat
- Whether weapons were involved
- The size, age, gender, and physical capabilities of the parties
- The nature, duration, and history of the relationship (particularly relevant in domestic cases)
- Any history of interaction or communication between the parties
- The nature and proportionality of the person’s response to the threat
- Whether there were other means available to respond to the threat
The proportionality question: Self-defence doesn’t require perfect proportionality, but the response must be reasonable. Using deadly force in response to a minor threat is almost never reasonable. Using significant force in response to a serious threat to your safety can be reasonable.
Common Self-Defence Scenarios
Bar Fights and Altercations
Scenario: Someone starts a fight with you in a bar. You fight back and injure them. You’re charged with assault causing bodily harm.
Self-defence analysis: Courts will examine:
- Who was the initial aggressor?
- Did you try to de-escalate or leave?
- Was your response proportional to the threat?
- Did you continue fighting after the threat ended?
If you responded to an unprovoked attack with reasonable force to defend yourself, self-defence may succeed. If you escalated the confrontation or retaliated excessively, it likely won’t.
Domestic Violence
Scenario: Your partner has been physically abusive for years. During an altercation, they attack you and you fight back, causing injury. You’re charged with assault.
Self-defence analysis: The law specifically recognizes the relevance of relationship history. Courts consider:
- The history of abuse in the relationship
- The power imbalance between parties
- Whether you reasonably feared for your safety
- The nature of your defensive response
Self-defence is frequently raised successfully by victims of domestic violence who fought back during an attack.
Defence of Others
Self-defence extends to protecting other people.
Scenario: You witness someone attacking a stranger on the street. You intervene physically to stop the attack and are charged with assault.
Self-defence analysis: You can defend another person if:
- You reasonably believed they were being attacked
- Your purpose was to defend them
- Your force was reasonable in the circumstances
Good Samaritan interventions are protected by self-defence law when the force used is reasonable.
What Is NOT Self-Defence
Retaliation: Once the threat has ended, continuing to use force is retaliation, not self-defence.
Disproportionate response: Using excessive force (e.g., stabbing someone who pushed you) is generally not reasonable.
Initial aggressor: If you started the altercation, claiming self-defence is much more difficult (though not impossible if the other person escalated beyond reasonable response).
Mutual combat: If you willingly entered into a fight (mutual combat), self-defence is harder to establish, though still possible if the other person escalated beyond what you expected or consented to.
Burden of Proof: Air of Reality
When you raise self-defence, you don’t have the burden of proving it. Instead, you just need to raise an “air of reality”—some evidence that self-defence might apply.
Once you’ve raised an air of reality, the Crown must prove beyond reasonable doubt that you were NOT acting in self-defence. This is a significant advantage for the accused.
Evidence Critical to Self-Defence Claims
Witness testimony: Independent witnesses who saw who started the altercation and the nature of the threat are invaluable.
Video evidence: Security camera or cell phone video can clearly show who was the aggressor and whether your response was reasonable.
Injury evidence: Your injuries demonstrate you faced a genuine threat. The complainant’s injuries show the level of force you used.
Text messages and communications: Prior threats from the complainant support your belief that force was about to be used.
Character evidence: In some cases, evidence about the complainant’s violent character or your peaceful character may be admissible.
The Role of Experienced Legal Counsel
Self-defence claims require careful legal strategy. You must establish the factual foundation (what actually happened) and apply the legal framework (Section 34 test). This requires:
- Thorough investigation and evidence gathering
- Strategic decisions about whether you should testify
- Effective cross-examination of Crown witnesses
- Understanding how to frame the narrative for the court
Assault Lawyers in Toronto with experience in self-defence cases understand how to present these claims effectively and maximize your chances of acquittal.
The Bottom Line
Self-defence is a complete answer to assault charges when you can establish you had reasonable grounds to believe force was being used against you, you acted to defend yourself, and your response was reasonable in the circumstances. Canadian law recognizes your right to protect yourself and others from unlawful violence.
However, self-defence is not a licence to retaliate or use excessive force. The law requires proportionality and defensive purpose. Successfully raising self-defence requires understanding the legal test, gathering supporting evidence, and presenting your case effectively.
If you’ve been charged with assault but were defending yourself, don’t assume the charges will simply be dropped. Self-defence must be properly raised and argued. With experienced legal representation, many people charged with assault while defending themselves secure acquittals or have charges withdrawn entirely.
Disclaimer: This article provides general legal information about self-defence law in Canada. It does not constitute legal advice. If you’ve been charged with assault and believe you were acting in self-defence, consult with a qualified criminal defence lawyer immediately.