The latest happened just before 7 p.m. Monday, when a 41-year-old motorcyclist travelling on Route 243 in Shefford, near Bromont, crossed the centre lane and collided with an oncoming van.
Police said the people in the van, a couple in their 50s, were not seriously injured.
Two hours earlier, 77-year-old cyclist was struck and trapped beneath the wheels of a tanker truck in the Mauricie town of Champlain.
The female cyclist was pronounced dead on the scene.
Driver killed, brothers survive
At around 5 p.m. Monday, a crash on Charlotte Road near Saint-Liboire in Montérégie killed one young driver and injured her teenage brothers who were passengers in the car.
Police said the vehicle collided head-on with an SUV that was travelling in the wrong direction.
The 18-year-old driver was pronounced dead in hospital. Her 14-year-old and 16-year-old brothers were treated for serious injuries. The truck driver was also seriously injured.
Three more people – a 33-year-old police officer, a 39-year-old man and a 57-year-old woman – were also killed in crashes over the weekend.