A loader control system includes: a boom position calculation unit configured to calculate a position of a boom rotatably supported by a vehicle body of a loader; a bucket attitude calculation unit configured to calculate an attitude of a bucket rotatably supported by the boom; a determination unit configured to determine whether the attitude satisfies a predetermined condition on the basis of the attitude and a reference attitude of the bucket in dumping movement; and a work machine control unit configured to cause the bucket to carry out the dumping movement, and output a control signal to cause the boom to carry out lifting movement when the attitude is determined to satisfy the predetermined condition.