Can a signed waiver stop me from suing for injury caused by negligence in Ontario?

Often, yes - a properly drafted, clearly presented waiver can bar or limit a negligence claim in Ontario for activities like gym use, adventure sports, or recreational programs, provided it clearly covers the type of incident that actually occurred and was properly brought to your attention before you signed it. Courts scrutinize waivers closely rather than enforcing them automatically, looking at whether the language was specific and clear enough to cover what happened, and whether it was presented in a way that gave you a genuine opportunity to understand what you were agreeing to, rather than being buried in fine print.

Waivers generally cannot exclude liability for the most serious kinds of misconduct, such as gross negligence or intentional harm, and their scope is always interpreted based on their actual wording rather than assumed to cover everything imaginable. The Occupiers' Liability Act separately allows occupiers to restrict or modify their duty toward visitors through clear notice or agreement, which overlaps with how waivers function in practice. Because enforceability depends heavily on the specific document and circumstances, a signed waiver is a serious obstacle to a claim, but never an automatic, guaranteed bar to it.