Each year in Sweden, approximately 6,900 children will have a parent diagnosed with cancer. Of all the children in Sweden born between 1990–1992, 5.6% have a parent with cancer and 1.1% of them have already had a parent die from cancer. Bereavement support is an important component in palliative care, which aims to alleviate the physical, psychological, and spiritual suffering of patients and their family members. Several, but not all families participating in the studies in this thesis came from a palliative care setting. Earlier research has shown that parentally bereaved children often experience psychological problems, physical problems, reduced self-esteem, difficulties communicating,school and behavioral problems, and/or complicated grief, with approximately 10% of parentally bereaved children experiencing some type of clinically significant psychological difficulty. Moreover, a child’s response to a parent’s death is often mediated by how their surviving parent responds to the loss. Still, support for bereaved children and families is limited in Sweden. The overall aim of this research project was to explore and describe psychological health, grief, and family communication among parentally bereaved children and surviving parents and to develop and evaluate a supportive family intervention. Four studies were conducted including an interview study exploring family communication in parentally bereaved families, a questionnaire study examining associations between family communication and psychological health in parentally bereaved children and adolescents, and the adaptation and evaluation of the Grief and Communication Family Support Intervention. Results from these four studies indicated that communication may be an important factor for adjustment following the death of a parent. Specifically, communication in some parentally bereaved families may involve conflict, which may in turn affect child and adolescent psychological health. Results from testing the Grief and Communication Family Support Intervention indicate that it may improve family communication and relationships. Testing the Grief and Communication Family Support Intervention with larger, more diverse samples is necessary to confirm these results. The results imply that helping families find ways to adjust and adapt in healthy ways following the death of a parent, potentially through the Grief and Communication Family Support Intervention, is likely to improve psychological health and communication among bereaved family members.