Workers' Memorial Day, also known as International Workers' Memorial Day or International Commemoration Day for Dead and Injured, takes place annually around the world on April 28, an international day of remembrance and action for workers killed, disabled, injured, or made unwell by their work. In Canada, it is commemorated as the National Day of Mourning.

A work accident, workplace accident, occupational accident, or accident at work is a "discrete occurrence in the course of work" leading to physical or mental occupational injury. According to the International Labour Organization (ILO), more than 337 million accidents happen on the job each year, resulting, together with occupational diseases, in more than 2.3 million deaths annually.