The collision happened on County Road 20 in North Grenville, just west of Oxford Station, at about 7:45 p.m. ET on Dec. 25.
A Toyota Tercel was heading west on County Road 20 when it struck a deer that had run across the road, Ontario Provincial Police said.
"The deer was vaulted into the air striking a 2005 Honda Civic travelling eastbound and hitting the male driver," OPP said in a media release.
The driver of the Civic, 31-year-old Roy Khabbaz, was pronounced dead at a hospital in Kemptville, Ont.
A passenger in his car wasn't injured. The two people inside the first vehicle also weren't hurt.
The road was closed for six hours while police investigated and it has since reopened.