A lane departure prevention system is provided with a lane departure tendency detection section, a yaw moment calculating section and a yaw moment control section. The lane departure tendency detection section detects a degree of a lane departure tendency of a host vehicle exhibiting a tendency of departing from its driving lane. The yaw moment calculating section calculates a base yaw moment to be applied to the host vehicle based on the degree of the lane departure tendency. The yaw moment control section applies the base yaw moment calculated by the yaw moment calculating section to the host vehicle when the base yaw moment is equal to or larger than a first prescribed minimum yaw moment, which is greater than zero, and applies the first prescribed minimum yaw moment to the host vehicle if the base yaw moment is smaller than the first prescribed minimum yaw moment.