York Regional Police say shots were fired at about 1 a.m. Friday at a banquet hall near on Creditstone Road, near Jane Street and Rutherford Road.
One man was shot in the head as he sat in a car. He was without vital signs when police arrived at the scene.
Police say a second man in the same car was shot in the stomach and later pronounced dead at Sunnybrook Hospital.
The victims' names and ages have not been released.