5 Common Mistakes That Can Sink Your Judicial Review Application in Ontario

Why Good Cases Sometimes Fail

Judicial review is one of the most important tools available to individuals who have been on the receiving end of an unreasonable or unfair government decision. But the process is unforgiving of mistakes. Strong cases are lost every year because of procedural errors that could have been avoided. Here are five of the most common pitfalls.

1. Missing the Filing Deadline

The single most common reason judicial review applications fail before they even get started is that they are filed too late. In Ontario's Divisional Court, the default timeline is 30 days from the date the decision is communicated. In the Federal Court, the typical deadline is also 30 days, though certain statutes impose shorter or longer periods. These deadlines are strictly enforced. While extensions of time can sometimes be obtained, the applicant must explain the delay and demonstrate that the underlying application has merit. Courts are skeptical of late applications, and a delay of even a few weeks without a good explanation can be fatal.

2. Failing to Exhaust Other Remedies

Before you can ask a court to review a decision, you must generally exhaust any internal remedies available to you. If the tribunal has a built-in appeal or reconsideration mechanism, you are typically required to use it first. Courts will decline to hear a judicial review application if the applicant has bypassed an adequate alternative remedy. This rule is not absolute — there are exceptions for cases involving pure questions of jurisdiction, constitutional issues, or where the alternative remedy would be inadequate — but ignoring it is a common and costly mistake.

3. Arguing the Merits Instead of the Standard of Review

One of the most difficult concepts in judicial review is that the court is not re-deciding your case. Many applicants come to court and essentially re-argue the facts, presenting their version of events and asking the judge to agree with them rather than the tribunal. But that is not how judicial review works. The question is not whether the court would have reached the same conclusion — it is whether the tribunal's conclusion was reasonable. Arguments must be framed in terms of the legal standard of review. You need to show that the decision lacked a rational basis, ignored key evidence, or was procedurally unfair — not simply that you disagree with it.

4. Introducing New Evidence

Judicial review is conducted on the record that was before the original decision-maker. Applicants frequently try to file new evidence that was not before the tribunal — updated medical reports, new witness statements, or additional documents they wish they had submitted earlier. Courts are extremely reluctant to admit new evidence on judicial review. There are narrow exceptions, such as evidence that goes to procedural fairness or evidence needed to provide background context, but the general rule is firm. The time to build your evidentiary record is at the tribunal level. If you did not present it there, you generally cannot present it on review.

5. Inadequate Written Submissions

Judicial review is a paper-heavy process. The application record, the tribunal record, and the written factum must all be properly prepared, organized, and served in accordance with the rules. A poorly organized record, a factum that fails to identify the standard of review, or submissions that ramble without making clear legal arguments can undermine even a strong case. Judges have limited time and heavy caseloads. If your submissions do not quickly and clearly articulate the legal error, you risk having a meritorious application dismissed.

The Bottom Line

Judicial review is a powerful remedy, but it demands precision. The deadlines are short, the procedural requirements are strict, and the legal arguments must be carefully tailored to the standard of review. Understanding these common mistakes — and avoiding them — can mean the difference between a successful challenge and a dismissed application. If a tribunal or government agency has made a decision that affects your rights, the time to act is now, not later.