First responders had to extricate the driver of a passenger vehicle that OPP were told was T-boned by a truck on Old Barrie Road at Line 4 in Oro-Medonte.
Police were alerted shortly after 5:45 on Thursday evening.
"Members of the public assisted those involved until emergency personnel arrived," OPP stated in a news release on Friday.
One of the drivers had to be extricated from the wreckage by firefighters and that person was transported to Royal Victoria Regional Health Centre in Barrie with serious but non-life-threatening injuries.
The intersection was closed for three hours while police investigated and the vehicles were removed.
The investigation is ongoing.
Orillia OPP request that any witnesses who have not already spoken to police or have dash cam footage of the collision, please call the Orillia OPP at 705-326-3536 or at 1-888-310-1122.