In a steering control system comprising a steering component having a steering wheel and a steering reaction force actuator, a turning component having vehicle turning wheels and a turning actuator, and a backup mechanism for alternately mechanically separating and linking the steering and turning components, there is provided a steer-by-wire control unit selectively separated from the backup mechanism for executing steer-by-wire control of the turning actuator to a turning angle corresponding to the steering condition and control of the steering reaction force actuator for imparting steering reaction force corresponding to the turning condition, a steering assistance control unit selectively linked to the backup mechanism for executing steering assistance control for at least one of the steering reaction force actuator and the turning actuator, and a control switching unit for controlling a shift, upon attainment of predetermined conditions, between control by the steer-by-wire control unit and control by the steering assistance control unit. The control switching unit, upon the shift of control, between the time of a separation/linkage command to the backup mechanism and the time of completion of separation/linkage, selectively sets as the correction amount the variation equivalence of the turning torque to be applied to the turning wheels of a vehicle after the completion and selectively executes correction of turning torque.