He began his rampage at a mechanical engineering class at the École Polytechnique, where he separated the male and female students, ordering the men to leave.

Some interpretations noted that the shooter had been abused as a child, or suggested that the massacre was the isolated act of a madman, unrelated to larger social issues.

Politicians in the House of Commons responded by passing more stringent gun control laws, and officials took other actions to end violence against women.

The massacre also led to policy changes in emergency services protocols to shootings; for instance, that police would intervene immediately to try to reduce casualties.

[5] Sometime after 4 p.m. on December 6, 1989, Marc Lépine arrived at the building housing the École Polytechnique, an engineering school affiliated with the Université de Montréal, armed with a Ruger Mini-14 rifle and a hunting knife.

He opened fire on the students, from left to right, killing six—Hélène Colgan, Nathalie Croteau, Barbara Daigneault, Anne-Marie Lemay, Sonia Pelletier, and Annie St-Arneault—and wounding three others, including Provost.

In these incidents, the police conducted rapid and immediate intervention, and improved coordination amongst emergency response agencies was credited with minimizing the loss of life.

[20][17] On December 6, 1989, the Montreal Police director of public relations Pierre Leclair briefed reporters outside the Polytechnique building; when he entered, he found the body of his own daughter Maryse among the dead.

[21] A joint funeral for nine of the women was held at Notre-Dame Basilica on December 11, 1989, and was attended by Governor General Jeanne Sauvé, Prime Minister Brian Mulroney, Quebec premier Robert Bourassa, and Montreal mayor Jean Doré, along with thousands of other mourners.

At age 14, Gamil changed his name to "Marc Lépine", citing his hatred of his father and taking his mother's surname to further separate from the man.

[28][38] The list included Pelletier, plus a union leader, a politician, a TV figure, and six police officers who the gunman knew from their playing together on an amateur volleyball team.

Government and criminal justice officials feared that extensive public discussion about the massacre would cause pain to the families and lead to more antifeminist violence.

[6][45] The media, academics, women's organizations, and family members of the victims protested the lack of a public inquiry and paucity of information released.

[11][28][46] The gender of the victims, as well as Lépine's oral statements during the massacre and in the suicide note, have resulted in the attack being interpreted as antifeminist and as an example of the wider issue of violence against women in Canadian society.

[6] Other psychiatrists emphasized the traumatic events of his childhood, suggesting that the blows he had received may have caused brain damage, or that he was psychotic, having lost touch with reality as he tried to erase the memories of a brutal (yet largely absent) father while unconsciously identifying with a violent masculinity that dominated women.

[59] Others framed the killer's actions as the result of societal changes that had led to increased poverty, powerlessness, individual isolation,[60] and polarization between men and women.

[67][68] They categorize it as a "pseudo-community" type of "pseudo-commando" murder-suicide, in which the perpetrator targets a specific group, often in a public place, and intends to die in "a blaze of glory".

[63] The injured and witnesses among university staff and students suffered a variety of physical, social, existential, financial, and psychological consequences, including post-traumatic stress disorder (PTSD).

Critics of the panel said that the plan failed to provide a workable timeline and strategy for implementation and that with more than four hundred recommendations, the final report was too diffuse to make an impact.

[33] Less than a week after the event, two École Polytechnique professors created a petition addressed to the Canadian government demanding tighter gun control; and more than half a million signatures were collected.

In 2009, survivors of the massacre, their families, and Polytechnique students past and present came together to create PolySeSouvient in opposition to legislative actions by Stephen Harper's Conservative government aimed at ending the registration of ordinary long guns.

[90] Since its creation, PolySeSouvient, with survivors Nathalie Provost and Heidi Rathjen as spokespersons, has continued to be active in lobbying for stricter gun control and safety in Quebec and Canada.

In 2018 Justin Trudeau's Liberal government introduced Bill C-71, which restored the requirement for sales of firearms to be registered,[90] but PolySeSouvient denounced the proposed regulations as ineffective and incomplete.

[96] On December 5th, 2024, one day before the anniversary of the massacre, the Government of Canada announced that they will be extending the previous 2020 "military-grade assault-style weapons ban" order in council with another OIC.

[110] René Jalbert, the sergeant-at-arms who persuaded Lortie to surrender, said that someone should have intervened at least to distract Lépine, but acknowledged that "ordinary citizens cannot be expected to react heroically in the midst of terror".

[21] Conservative newspaper columnist Mark Steyn suggested that male inaction during the massacre illustrated a "culture of passivity" prevalent among men in Canada, which enabled the shooting spree.

[118][119] Since the commemorative ceremony on the 25th anniversary of the massacre in 2014, fourteen searchlights representing the women killed have been installed annually on the summit of Mount Royal.

The critically acclaimed movie Polytechnique, directed by Denis Villeneuve, was released in 2009 and caused discussion over the desirability of reliving the tragedy in a mainstream film.

[100][129] In 2009 Quebec playwright Gilbert Turp wrote Pur chaos du désir, which examined a marriage breakdown in the aftermath of the Polytechnique killings.

[100][129] Several songs have been written about the events, including "This Memory" by the folk duo the Wyrd Sisters,[24] "Montreal"' by The Tragically Hip[130][131] and "6 December 1989" by the Australian singer Judy Small.