The specific influence of parents and peers on adolescents' educational aspirations is examined in a relational sample of matched adolescent-parent-best friend triads (N=762). A nonrecursive model of peer influence is also estimated. Most previous estimates of interpersonal influences are based on the adolescent's perceptions of the significant other's attitudes or behaviors rather than on the significant other's self-reports of these attributes. Estimates of interpersonal influences based upon self-reported attributes are presented. It is shown that perceptual measures inflate estimates of interpersonal influence. Independent data from parents document that perceptual measures of significant others' attributes reflect not only attributes of the person being perceived but also attributes of the perceiver. Parental influence on the adolescent's aspirations is stronger than peer influence, and this influence does not decline over the adolescent years. Peers are involved in a process of reciprocal influence, and peer influences are stronger among girls than among boys.