The officer was patrolling Highway 6 between 2nd Line and 4th Line in Centre Wellington Township, about 21 kilometres northwest of Guelph, in a marked OPP vehicle just after 9 p.m., police said in a release.
He pulled the police vehicle to the side of the road, put on the rear flashing lights and got out of the car. As he was getting out, he was in hit the face by a black plastic snow scraper, police said.
The OPP say they don't have any descriptions of suspects or the vehicle.
The officer was treated in hospital for minor facial injuries and has been released.