The proposed trial will test the efficacy of the parent-focused clinic-based Parent Uncertainty Management Intervention (PUMI) to improve the outcomes of children newly diagnosed with cancer and their parents. Participants will be randomly assigned to receive equivalent doses of either the PUMI or an Education/Support (ESO) group. Theoretically driven by Mishel's model of illness uncertainty, the PUMI will teach parents about uncertainty prevention and management through the use of medically-specific communication, information management, and problem-solving skills via in-clinic sessions and an online portal. Parents and children will complete measures online at baseline, 1-week, and 3-, 6-, and 12-month follow-ups.