A lane keeping assist system for performing lane keeping using information about a lane and peripheral vehicle may include an image sensor configured to detect a forward lane and a preceding vehicle with respect to a host vehicle, and an electronic control unit (ECU) configured to control a traveling direction of the host vehicle in a manner that the host vehicle follows a traveling route within the detected lane, perform a preceding vehicle follower control to control the traveling direction of the host vehicle in a manner that the host vehicle follows the preceding vehicle if the lane is not detected, and restrict a follower longitudinal control if the preceding vehicle deviates from an expected path of travel.