Peer rejection is important in gaining an understanding of children’s social development. It is typically defined in terms of a sociometric nomination procedure in which classroom peers are provided either with photographs or with a list of names of all of the children in a classroom. Children are then asked to nominate three peers who they most like to play with and three peers who they most dislike to play with. A social preference score is computed in which children’s dislike scores are subtracted from their like scores. Rejected children have a social preference score of less than −1.0, a social impact score, a like score of less than 0, and a dislike score of greater than 0. This entry reviews predictors and developmental outcomes ...