A work vehicle control system includes an actual topography acquisition device, a storage device, and a controller. The actual topography acquisition device acquires actual topography information which indicates an actual topography of a work target. The storage device stores design topography information which indicates a final design topography which is a target topography of the work target. The controller acquires the actual topography information from the actual topography acquisition device. The controller acquires the design topography information from the storage device. The controller generates a command signal to move the work implement along a first locus that follows a slope of the actual topography, and a second locus positioned above the actual topography and below the final design topography in front of the first locus.