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 6 months of diagnosis, with almost half favoring within 2 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.