Emotional responses to negative daily experiences in young adolescents may provide important clues to the development of psychopathology, but research is lacking. This study assessed momentary mood reactivity to daily events as a function of risk profile in a school sample, ages 11-14. High-risk (HR, n = 25) and low-risk (LR, n = 106) subgroups completed frequent self-reports of mood and events for 5 days. HR adolescents reported more negative events involving family and peers. Multilevel modeling results showed that negative events, especially if stressful, were associated with increased negative and decreased positive affects, with heightened responses in HR adolescents. HR adolescents with greater stress over the last 3 months showed additional increases in depressed mood following negative events. Altered reactivity to and dysfunctional appraisals of daily events may link adolescent risk profiles to later mental health problems.