Background: To determine physical and psychosocial well-being of adolescents with type 1 diabetes by self-report and parent report and to explore associations with glycemic control and other clinical and socio-demographic characteristics. Methods: Demographic, medical and psychosocial data were gathered from 4 participating outpatient pediatric diabetes clinics in the Netherlands. Ninety-one patients completed the Child Health Questionnaire-CF87 (CHQ-CF87), Centre for Epidemiological Studies scale for Depression (CES-D), and the DFCS (Diabetes-specific Family Conflict Scale). Parents completed the CHQ-PF50, CES-D and the DFCS. Results: Mean age was 14.9 years (± 1.1), mean HbA1c 8.8% (± 1.7; 6.2-15.0%). Compared to healthy controls, patients scored lower on CHQ subscales role functioning-physical and general health. Parents reported less favorable scores on the behavior subscale than adolescents. Fewer diabetes-specific family conflicts were associated with better psychosocial well-being and less depressive symptoms. Living in a one-parent family, being member of an ethnic minority and reporting lower well-being were all associated with higher HbA1c values. Conclusion: Overall, adolescents with type 1 diabetes report optimal well-being and parent report is in accordance with these findings. Poor glycemic control is common, with single-parent families and ethnic minorities particularly at risk. High HbA1c values are related to lower social and family functioning.