Peer victimization is a widespread phenomenon especially prevalent in early adolescence. This study investigates the prevalence of peer victimization and its association with mental health problems and impact on everyday life, and the possible mediating effect of parental and peer support. Data are based on a cross-sectional health survey (N = 9,707) among adolescents (10-13 years) and their parents (N = 8,210). The Strengths and Difficulties Questionnaire was used to measure mental health problems, as well as impact on everyday life. Approximately, 17.6% of boys and 15.3% of girls reported being peer victimized. Both genders had higher symptoms of emotional problems, conduct problems, and hyperactivity than non-peer victimized adolescents. Boys had higher symptoms of emotional problems than girls. All symptom scales were strongly associated with perceived impact on everyday life. Peer and parental support buffer mental health problems among the victimized. Study indicates the importance of interventions strengthening peer support among victimized early adolescents.