Can I sue my insurance company for denying a claim I believe is covered in Ontario?

Yes. An insurance policy is a contract, and if your insurer denies a claim you believe is properly covered, you can sue for breach of that contract to recover what the policy should have paid. The core question is whether your loss actually falls within the policy's coverage grant and whether any exclusion the insurer is relying on genuinely applies - insurers bear the burden of proving an exclusion applies once you've shown your loss generally fits within the coverage the policy provides.

Before suing, it's worth understanding exactly why the claim was denied - insurers are generally expected to explain their reasons, and a vague or shifting explanation can itself be a sign the denial doesn't hold up. Your policy wording, the denial letter, and your proof of loss documentation are the core evidence in these disputes. In some cases, if the insurer's handling of the claim itself was unreasonable - not just a wrong decision, but an unfair process - you may also have grounds to claim damages beyond the policy amount for bad faith in how the claim was handled, which is a separate and higher bar than simply having a claim wrongly denied.