The collision occurred at Rutherford Road and Williams Parkway. Peel Regional Police were called to the scene at 6:10 p.m.
Const. George Tudos told CBC News that at least four people have been injured.
Tudos said three had suffered "very serious" injuries.
Four patients in serious condition were transported to Brampton Civic Hospital, Peel Regional Paramedics Services confirmed. None of the people are in life-threatening condition.