Dagenais v Canadian Broadcasting Corp, [1994] 3 S.C.R. 835 is the leading Supreme Court of Canada decision on publication bans and their relation to the right to freedom of expression under section 2(b) of the Canadian Charter of Rights and Freedoms. It was held that judges have a common law discretionary authority to impose publication bans on information revealed in a criminal trial. The judge, however, must weigh competing rights, such as freedom of expression and right to a fair trial, to mizzen the violation of rights. It was further held that the media has a right to appeal a decision of a publication ban.

Four former and present members of the Christian Brothers, a Catholic order, were charged with sexual abuse of young boys while they were teachers at an Ontario Catholic school. During their trial the Canadian Broadcasting Corporation produced a dramatic mini-series, based on another sexual abuse scandal at Mount Cashel Orphanage, named The Boys of St. Vincent, and it was scheduled to be broadcast nationwide in the first week of December, 1992. The defence brought an application requesting the jury be charged before the airing of the show or else sequestered over the weekend of the show's airing. The judge declined and instead merely directed the jury to avoid watching the show.

The day before the airing the defence applied for an injunction to restrain the CBC from broadcasting the show and from publishing any information relating to the show until the last of the four trials were over. The injunction was granted.

On appeal, the Court of Appeal for Ontario upheld the injunction but limited it only to Ontario and Montreal, and overturned the ban on any publicity of the show. The CBC and the National Film Board of Canada appealed the decision to the Supreme Court of Canada.

The majority of the Court held that the publication ban was in violation of the freedom of expression under section 2(b) of the Charter.

The Court set out a test for a publication ban to be granted, and this has since become known as the Dagenais/Mentuck test:^[1]

… A publication ban should only be ordered when:

(a) Such a ban is necessary in order to prevent a real and substantial risk to the fairness of the trial, because reasonably available alternative measures will not prevent the risk; and

(b) The salutary effects of the publication ban outweigh the deleterious effects to the free expression of those affected by the ban. …

Smith J stated in a 2014 judgment that:^[2]

The Supreme Court of Canada has closely guarded the open court concept over the years and in the last 20 years has narrowed the test for the use of discretionary orders to ban the publication of evidence in Dagenais v. Canadian Broadcasting Corp, and R v Mentuck, known as the "Dagenais-Mentuck" test. The "Dagenais-Mentuck" test requires the party opposing media access to demonstrate that the order (for the ban) is necessary to prevent a serious risk to the proper administration of justice and that the salutary effects of the order sought outweigh the deleterious effects on the rights and interests of the parties and public.

• List of Supreme Court of Canada cases (Lamer Court)

• Full text of Supreme Court of Canada decision at LexUM and CanLII