At approximately 1:00 p.m., Halton Regional Police responded to a shootout in the area of 484 Plains Road East.
At around 2 p.m., police confirmed that one of the victims died of his injuries, while another was hospitalized.
At least one suspect has fled the scene and is currently on suspicion, police said.
There is currently no word on a possible reason.
The investigators ask anyone with information or surveillance videos or dashboard cameras in the area to contact the police.
Plains Road East is currently closed back and forth between King Road and Waterdown Road during the police investigation.
There does not appear to be an immediate threat to public safety, said the police.
Police are asking people to avoid the area.