A vehicle turn-over determination apparatus includes a turn-over sensor, a memory, a determination processor, and a road-surface detector. The turn-over sensor detects a value of a turn-over angle or a turn-over velocity of a vehicle. The determination processor performs the determination of the turn-over of the vehicle on the basis of the value detected by the turn-over sensor and the determination-threshold information held in the memory. The road-surface detector detects a road surface that is present in a traveling direction of the vehicle. The determination processor varies the determination-threshold information acquired from the memory in accordance with an inclination of the road surface detected by the road-surface detector, and thereby generates adjusted-threshold information adjusted in accordance with the inclination of the road surface. The determination processor compares the adjusted-threshold information and the detected value with each other, and thereby perform the determination of the turn-over of the vehicle.