The accident happened Sunday afternoon in the southbound lane of Highway 63, about five kilometres south of Wandering River.
RCMP say the motorbike with just one rider aboard was following the trailer when the driver of the tow vehicle slowed to make a left-hand turn.
They say a 49-year-old man who was driving the bike couldn't slow down in time to avoid a collision.
The victim — a resident of Onoway, Alta., — died at the scene.
Mounties say speed and alcohol have not been ruled out as factors in the collision.