An apparatus for controlling start-up of a lane keeping assistance system (LKAS) which prevents lane departure of a first vehicle includes a detecting unit configured to detect a second vehicle which is traveling in a neighboring lane, a dividing line interposed between the first vehicle and the second vehicle, and a start-up controlling unit configured to determine a weighting factor based on a detection result of the detecting unit, change parameters which control a time point of the start-up of the LKAS based on the determined weighting factor, and control the time point of the start-up of the LKAS based on the changed parameters.