The most recent, and worst in terms of fatalities, happened Sunday afternoon at around 4:20 p.m. CST, when three teenage boys were killed on Highway 6.
The crash involved four vehicles at a highway construction site about five kilometres south of Spalding.
Three teenage boys, ages 14, 15 and 17, all from Carrot River, died after the car they were in was rear-ended by a semi-truck.
In a chain reaction, the car hit a pickup truck, which then struck a construction vehicle and a flag man who was working at the site.
The flag man was taken to hospital in critical condition.
Meanwhile, a 15-year-old girl died when a pickup rolled on a grid road about 50 kilometres northwest of Swift Current.
The driver, a 16-year-old girl, and another passenger, an 18-year-old girl, were taken to hospital with serious injuries.
It happened around 5:20 a.m. CST, the RCMP said.
Officers believe the truck rolled after the driver lost control.
Another fatal crash happened later Sunday morning that left two people dead near Estevan.
A semi-truck and a smaller vehicle collided Sunday morning shortly after 9 a.m.
Police said that the smaller vehicle ignited and was burned "beyond recognition."
On Saturday afternoon, a man, 20, died when he was ejected from a vehicle after it crashed on the Okanese First Nation, about 14 kilometres northeast of Balcarres.
Two other passengers in the car suffered non-life-threatening injuries. A fourth passenger was located after he left the scene.
Police say alcohol was likely a factor in the crash.
None of the victim's names have been released.