Several neighbours said they were awoken by as many as 10 gunshots just after 2 a.m. PT in the 2500-block of 204 Street.
The neighbours, all of whom declined to give their names, said the house is believed to be a legal marijuana grow operation. An officer on scene said he didn't believe that's why the house and its occupants were targeted, blaming hard drugs, instead.
More than a dozen orange cones could be seen in front of the house, where officers were focusing their investigation.
Langley RCMP said one of the shooting victims was taken to hospital in serious condition, the other two aren't hurt as badly.
Police said no suspects have been arrested.