Family-based interventions in pediatric cancer face challenges associated with integrating psychosocial care into a period of intensive treatment and escalating stress. Little research has sought input from parents on the role of interventions delivered shortly after diagnosis. This mixed-methods study obtained parents’ perspectives on the potential role of family-based interventions. Twenty-five parents provided feedback on the structure and timing of psychosocial interventions via focus groups and a questionnaire. Qualitative analyses resulted in three themes that were illustrative of a traumatic stress framework: 1) tension between focusing on child with cancer and addressing other family needs, 2) factors influencing parents’ perception of a shared experience with other parents, and 3) the importance of matching interventions to the trajectory of parent adjustment. Quantitative data indicated that parents preferred intervention within six months of diagnosis, with almost half favoring within two months of diagnosis, and the majority wanted interventions targeted to parents only. Qualitative themes highlight the importance of using a traumatic stress framework to inform the development of family-based interventions for those affected by pediatric cancer.