What is passing off and can I sue a competitor for it even without a registered trademark?

Passing off is a common-law tort that protects the goodwill a business has built in its name, branding, or overall look, even without any trademark registration. To succeed, you generally need to show three things: that your business has genuine goodwill or reputation associated with the name or branding, that the competitor's use of something similar is likely to deceive or confuse customers into thinking there is a connection between the two businesses, and that you have suffered, or are likely to suffer, actual damage as a result — typically lost sales or harm to reputation.

Because there is no registration to point to, proving passing off tends to be more evidence-intensive than a registered-trademark claim: you need to show your reputation actually exists in the specific market and area where confusion is happening, not just that you used the name first. This makes passing off realistic mainly for businesses with an established, recognizable presence rather than a very new business with limited public recognition. It remains a genuinely available legal route in Ontario, and a court can order the competitor to stop and potentially award damages, but success is not guaranteed and depends heavily on the specific facts and evidence available.