As predicted, children who experienced more peer problems at school, such as feeling excluded by friends or being teased, during the week showed, on average, a contextual shift toward more negative mood and feelings of less competence and self-worth from mornings at home to afternoons at school during the week of data collection. Interestingly, peer problems no longer predicted state self-esteem in school when academic problems were controlled in a regression analysis. Academic problems appear to have a stronger or more direct impact on children’s self-evaluations at school than do problems with peers. The research suggests that peer relationships are important to attend to in school, in addition to academic problems, because they are associated with negative subjective states during school hours. In severe cases, the experience of negative states in school might lead to school refusal among children and adolescents. This study explored the link between peer problems in school and contextual variations in negative mood and state self-esteem over a 5-day period. Tables, figure, and references