If my conduct was bad but not bad enough for cause, can a court still cut my notice period?

Generally no. Ontario courts have rejected the idea of "near cause" — the notion that misconduct falling short of just cause should still shrink your reasonable notice period. The question is treated as all or nothing: either the employer proves conduct serious enough to justify dismissal without notice, or you are entitled to full common-law reasonable notice as if the misconduct had not occurred.

That matters because employers sometimes plead cause, fail to establish it, and then argue the notice award should be trimmed anyway because you were a difficult or underperforming employee. That argument does not succeed on its own. Your notice period is driven by the established factors — length of service, age, the character of the position, and how readily comparable work can be found.

Misconduct can still affect the outcome in other ways. It may support a cause defence if more evidence emerges, it may bear on whether you properly mitigated your losses, and an employer who alleges cause without a reasonable basis can face consequences in costs. If your employer has alleged cause, get the allegation assessed early — how it is answered shapes the whole claim.