Siblings of children with cancer can endure great psychological distress as a result of their brother's or sister's diagnosis and treatment. Understandably, when a child has cancer, their parents' attention is focused mainly on that child and therefore the siblings' needs may not be fully addressed. Thus, siblings often develop feelings of anger, abandonment, jealousy, and fear, which may lead to an increased risk for academic difficulties, symptoms of depression and anxiety and post traumatic stress disorder, although the results are not consistent across studies. Of most concern is that psychological problems may persist through adulthood, as suggested by a recent study in which alcoholism was more prevalent among siblings of children with cancer when compared to peers and cancer survivors. Therefore, it is imperative to develop evidence based psychological intervention programs to prevent these detrimental psychological effects in siblings of children with cancer. This project aims to address siblings' psychological distress by assessing the efficacy of a manualized group intervention for siblings of children with cancer (SibCT) across three Canadian sites (SickKids, Alberta Children's Hospital, BC Women and Children's Hospital) using a randomized control trial (RCT) experimental design. A manualized intervention is considered the gold standard for psychological intervention as it ensures replicability of the study and intervention fidelity. The primary aim is to demonstrate that survivors in the SibCT group (EG) demonstrate decreased symptoms of depression and anxiety improve their overall quality of life compared to an attention control group (CG). A secondary aim is to show that compared to CG, EG will show improvements in secondary measures of quality of life as well as knowledge about cancer. We will also explore other factors such as disease and treatment variables, social contextual variables, individual (sibling) variables and family variables. Randomized Control Trial design with repeated measures will be used. Siblings of children on active cancer treatment and at least 3 months from diagnosis to reduce parental burden; between 8-16 years of age will be included in the study. Siblings will be randomized to either the EG or CG. Approximately 184 siblings will be recruited across the three pediatric centres. After baseline assessment, both groups will have 8 two-hour weekly group sessions consisting of arts and crafts and games, and two post-intervention assessments; at the end of session 8 and three months later. In the EG the critical ingredient has education and social and therapeutic problem solving components based on the manual. Examples of weekly session topics include: age-appropriate medical information about cancer; siblings' fears and feelings; relationships at school, etc. The CG will not have any education or therapeutic-based components. Rigorous testing of the efficacy of an intervention program is a critical step for developing evidence-based treatments.