Two people were removed by first responders from the wreckage of a vehicle that crashed around 3 p.m. on Sunday in the area of Diamond Valley Drive and Line 7 north in Oro-Medonte.
Orillia OPP say it was reported that the vehicle left the road striking a hydro pole and rolling onto its side.
Both occupants were transported to Royal Victoria Regional Health Centre in Barrie.
According to police, the driver escaped with minor injuries, and the passenger suffered serious injuries.
Line 7 north between Diamond Valley Drive and Bass Lake Sideroad was closed for about six hours.
"The investigation is ongoing. No further details to be released at this time," OPP stated in a media release.