How do I withdraw or discontinue a lawsuit in Ontario after I have filed it?

In Ontario civil litigation, a plaintiff who wishes to withdraw their claim after filing it must generally file a Notice of Discontinuance with the court. Under Rule 23 of the Rules of Civil Procedure, a plaintiff may discontinue an action without a court order, subject to important conditions: it must be done before the defendant has filed a defence, or by consent of all parties, or with leave of the court.

If you discontinue an action, the general default rule is that you are liable to pay the defendant's costs up to that point, unless the parties agree otherwise or the court orders differently. This is an important financial consideration — walking away from a lawsuit can still trigger a costs obligation to the party you were suing.

A voluntary discontinuance does not always prevent you from suing again on the same claim (unlike a dismissal on the merits), but it can have strategic consequences. If you discontinue and later try to bring the same claim again, the second proceeding may face procedural challenges, and the limitation period will have continued to run. Any discontinuance, particularly one that might affect your rights to sue again or exposes you to costs liability, should be discussed with a lawyer before you file the paperwork.