Previous research has revealed grade-related changes in organization underlying children's ratings of aggression and withdrawal in their peers (\ounger, Schwartzman, & Ledingham, 1985). The present investigation examined the contributions to such changes of age-related differences in the perspective of the raters (age of rater) and in the behavior of the children rated (age of children rated). Study 1 examined teacher ratings of aggression and withdrawal in first-, fourth-, and seventh-grade children in order to assess effects attributable to age of children rated. In contrast to earlier findings with peer raters, no differences were found across grade level in the organization of teacher ratings. Study 2 examined age of rater differences in the organization of first-, fourth-, and seventh-grade children's beliefs about behavior that might be displayed by hypothetical peers. Differences were found that paralleled those observed earlier in children's actual peer ratings. Study 3 examined first-and seventh-grade children's ratings of peers who were older or younger than the raters, to assess the influence of age of rater on children's ratings. Age of rater effects emerged even when children rated peers who were not their age mates. These findings suggest that differences across grade level reported in children's peer ratings largely reflect differences in the child raters' view of behavior. Implications of these findings for the use of peer evaluations are discussed.Childhood peer relations have assumed a role of central importance in the assessment and classification of childhood psychopathology (Achenbach & Edelbrock, 1978;Quay, 1979;Ross, 1980). How children relate to their peers has not only served as a means for classifying childhood behavior problems but has also been found to provide a valuable predictive index of later functioning in adolescence and adulthood (Kohlberg, LaCrosse, & Ricks, 1972;Roff, Sells, & Golden, 1972). Because children represent actual participant-observers of the social behavior of their peers and may consequently view such behavior from a unique perspective, investigators have also increasingly chosen children to serve as assessors of the social functioning of their peers. Indeed, it has been argued that the assessment of peer opinion provides the investigator with unique information