A steering control system is disclosed for use with a machine. The steering control system may have left and right motors, at least one input device configured to generate first and second signals indicative of desired speed and desired steering, a left speed sensor configured to generate a third signal, and a right speed sensor configured to generate a fourth signal. The steering control system may further have a controller configured to determine a difference between desired and actual steering based on the second, third, and fourth signals, to determine a steering command change that should be implemented based on the difference, and to determine a gain based on the second signal. The controller may also be configured to adjust the steering command change as a function of the gain, and to selectively apply the adjusted steering command change to one of the left and right motors.