Who pays costs if I lose a motion in an Ontario lawsuit?

Costs on a motion generally follow the same "loser pays" principle that applies to the lawsuit as a whole. Under the Courts of Justice Act, judges have broad discretion over costs, and the Rules of Civil Procedure govern how costs are calculated, so a party who brings or opposes a motion unsuccessfully is usually ordered to contribute to the other side's legal costs for that specific motion, separate from costs for the case overall. This means winning a motion isn't free even if you ultimately win the whole lawsuit later — a party can be ordered to pay costs of an individual motion they lost along the way, regardless of how the broader case eventually turns out.

The amount awarded is at the judge's discretion and typically reflects the partial indemnity scale rather than a party's full actual legal bill, though the exact figure depends on the complexity of the motion, how it was argued, and the conduct of the parties. A judge can also reserve costs to be decided later, order costs regardless of the outcome in unusual circumstances, or increase costs where a motion was brought unreasonably or in bad faith. Because costs exposure applies motion by motion, it's worth weighing whether a procedural fight is actually worth bringing before filing it.