Background: Pediatric cancer diagnosis and treatment can impact the psychological adjustment and quality of life (QOL) of caregivers. Objectives: We examined: (a) the relationship between caregiver QOL and family psychosocial risk, mental health symptoms and distress concurrently, shortly after diagnosis, and six months later; and (b) which of these factors at near diagnosis can predict caregiver QOL six months later, controlling for demographic and child clinical factors. Methods: Participants were 122 caregivers in two Canadian sites. Each completed the Caregiver Quality of Life Cancer Scale, the Psychosocial Assessment Tool (PAT), the Distress Thermometer (DT), and the Hospital Anxiety and Depression Scale (HADS) near diagnosis (T1) and six months later (T2). Clinical and demographic information were also collected. Results: Clinical and demographic factors were not associated with QOL at either T1 or T2. Concurrent analyses (within T1 and T2) indicated the PAT, DT, and anxiety symptoms as significant factors contributing to caregiver QOL. Longitudinally, only T1PAT and depression symptoms significantly predicted caregiver QOL at T2. Family psychosocial risk and caregiver depression symptoms near diagnosis predict caregiver QOL six months later. These results have important implications for supporting caregivers of children with cancer. Highlights: Childhood cancer diagnosis and treatment can negatively impact on the quality of life (QOL) of caregivers of the affected child. High family psychosocial risk and elevated caregiver depression symptoms near the child's cancer diagnosis can predict poor caregiver QOL six months later. Conclusions: Early assessment of family psychosocial risk and caregiver mental health, particularly depression symptoms, can guide psychological support and prevent poor caregiver QOL. Considering the close relationship between the wellbeing of the child and caregiver, addressing caregiver mental health needs can positively impact on the QOL of the caregiver and the child with cancer.