The International Day Against Homophobia and Transphobia was initiated in 2003 in Quebec by the Fondation Émergence. May 17 is a reference to May 17th, 1990, the date the World Health Organization removed homosexuality from its list of mental illnesses.

May 17th is an opportunity to raise awareness among the general public about the issues faced by LGBTQ+ people and to take action to make the world more inclusive of sexual and gender diversity.