An injunction is a court order that restrains a person or company from doing something, or in some cases requires them to do something. In Ontario, the Superior Court of Justice may grant an interlocutory injunction or a mandatory order where it appears just or convenient to do so.

The main categories are:
interlocutory injunctions granted before the case is finally decided;
without-notice injunctions granted on an emergency basis for a short period;
mandatory injunctions that compel affirmative action; and
permanent injunctions granted after trial or final adjudication where lasting relief is required. Ontario’s rules also recognize related remedies such as certificates of pending litigation, and the Commercial List publishes model orders for Mareva and Anton Piller relief and maintains authorities for Norwich Pharmacal orders.

The usual test comes from RJR-MacDonald. The moving party must show:

1. a serious question to be tried;
2. irreparable harm if relief is refused; and
3. that the balance of convenience favours the order.

It is a relatively low threshold. The court is not conducting the full trial on the motion; it is making a preliminary assessment to ensure the claim is not frivolous or vexatious and that there is a real issue worth preserving until the merits can be decided.

“Irreparable” refers to the nature of the harm, not simply its size. It means harm that cannot be adequately compensated in money or cannot practically be cured later, often because damages would not be an effective remedy.

It is the court’s way of asking which side should bear the interim risk while the case is still pending. The court weighs the harm from granting relief against the harm from refusing it.

A mandatory injunction does not merely stop conduct; it compels positive action, such as restoring access, returning property, or reversing an interim step. Because it is more intrusive, the first-stage merits threshold is higher: the applicant must show a strong prima facie case, not just a serious issue to be tried.

Yes, but only in limited circumstances. Ontario Rule 40.02 allows an interlocutory injunction or mandatory order to be granted without notice for a short period, and Rule 39.01(6) requires the moving party to make full and fair disclosure of all material facts. Failure to do so is itself sufficient ground to set the order aside.

In ordinary civil matters, a without-notice interlocutory injunction or mandatory order may be granted for no more than 10 days initially. A further without-notice extension is also capped at 10 days, and ordinary extensions are meant to proceed on notice unless exceptional circumstances justify otherwise.

Not always fully, but there must generally be a pending or intended proceeding. Ontario Rule 40.01 says an interlocutory injunction or mandatory order may be obtained on motion by a party to a pending or intended proceeding.

For ordinary civil and commercial matters, injunctions are generally sought in the Superior Court of Justice. Ontario’s statutory scheme also makes clear that equitable relief is granted by the Superior Court or the Court of Appeal, not Small Claims Court.

No. Ontario’s Courts of Justice Act provides that only the Court of Appeal and the Superior Court of Justice, exclusive of Small Claims Court, may grant equitable relief unless otherwise provided.

Usually yes. Rule 40.03 provides that, unless the court orders otherwise, the moving party must undertake to compensate the responding party for damage caused by the injunction if it later appears the order should not have been granted.

Injunctions are evidence-driven. Rule 39.01(4) allows affidavits on motions to include statements based on information and belief if the source and fact of the belief are specified, and Rule 39.02 allows cross-examination on affidavits in the proper case. In practice, strong injunction records usually include a clear chronology, disciplined affidavit evidence, and documents showing the legal right, the urgency, and why damages are not enough.

A party affected by an order obtained without notice may move promptly under Rule 37.14 to set it aside or vary it. The motion must be served forthwith after the order comes to that person’s attention and must name the first available hearing date at least three days after service.

Where the facts justify true urgency, Ontario’s rules allow very rapid motion practice, including without-notice relief in appropriate cases. The key point is that the rules permit urgent interim relief, but the court still expects a disciplined evidentiary record and proper procedural footing.

Yes. Rule 40.04 requires each party on a Rule 40 motion to serve a factum, and the moving party’s factum must generally be served and filed at least seven days before the hearing.

A breach of a clear order can lead to civil contempt proceedings. The Supreme Court of Canada has held that civil contempt requires proof beyond a reasonable doubt of an intentional act or omission that breaches a clear order of which the person had notice.

Often yes, but the appeal route depends on whether the order is interlocutory or final. Ontario’s Divisional Court guidance explains that appeals from interlocutory orders of a Superior Court judge generally go to the Divisional Court with leave.

An interlocutory injunction is temporary and is meant to preserve the position while the case is ongoing. A permanent injunction is final relief after rights have been determined. The Supreme Court in Google v. Equustek expressly noted that the RJR-MacDonald interlocutory test does not apply to an order that is effectively final.

Yes. A permanent injunction may be granted after trial or final adjudication where damages or declarations alone would not adequately protect the right going forward. Ontario’s courts have equitable jurisdiction, and permanent injunctions are a recognized form of final equitable relief.

Depending on the problem, related remedies may include:
a Mareva injunction to freeze assets,
an Anton Piller order to preserve evidence through civil search relief,
a Norwich order to compel targeted third-party disclosure, and
a Certificate of Pending Litigation where an interest in land is in issue. Ontario’s Commercial List publishes model orders for Mareva and Anton Piller relief and maintains authorities for Norwich Pharmacal orders, while the Courts of Justice Act separately governs CPLs.

A CPL is used when a proceeding puts an interest in land in question. Under s. 103 of the Courts of Justice Act, a proceeding is not notice to non-parties until the court issues a CPL and it is registered in the proper land registry office. A party who registers a CPL without a reasonable claim to an interest in the land can be liable for damages.

Yes. Labour injunctions are governed by s. 102 of the Courts of Justice Act, which has its own notice, evidence, and timing rules. Rule 40.02(4) also expressly says the ordinary 10-day without-notice regime in Rule 40.02(1) to (3) does not apply to labour-dispute injunctions.

Usually when damages are an adequate answer, when the alleged harm is speculative rather than real and imminent, when the order sought is vague or overbroad, or when the moving party cannot establish the core test. Injunctions are exceptional, evidence-heavy remedies; they are not granted simply because a dispute feels urgent.