The relations of parental differential treatment perceived by children to their self-esteem were examined. The subjects were 299 fifth-and sixth-grade elementary school children (162 boys and 137 girls) in Seoul. The data were collected using two kinds of questionnaires on maternal and paternal differential treatment and a child’s self-esteem. The major findings are as follows: Firstborns received more differential maternal affection than secondborns, and both boys and firstborns received more differential maternal control than girls and secondborns. Differential paternal control varied as a function of a child’s sex and birth order, in which boys and firstborns received more differential paternal control than girls and secondborns, but differential paternal affection did not vary. Maternal differential treatments were related to self-esteem only in girls, indicating that the more differential maternal affection they perceived, the higher self-esteem they had, and the more differential maternal control they perceived, the lower self-esteem they had. Paternal differential treatments were not related to self-esteem both for boys and girls. The study emphasizes the crucial role of mothers on their daughters.