Lane-keep control system for vehicle

A lane-keep control system for a host-vehicle is arranged to execute a lane-keep control for moving the host-vehicle in a traveling lane, to determine whether there is an approaching-vehicle behind the host-vehicle (S1), to increase an intervention threshold (TTH) when there is the approaching vehicle behind the host-vehicle, and to suspend the lane-keep control when a steering control indicative value due to driver intervention is greater than the intervention threshold.