Objective: Breaking Bad News (BBN) is challenging in pediatric oncology. It requires tailored, sensitive communication to families and children at critical moments. However, pediatric oncology lacks context-specific BBN support tools. The OKRA project aims to address this gap by developing and refining a support tool with a participatory approach. Methods: The OKRA-Compass was developed using a participatory action research (PAR) approach with mixed methods. It involved iterative refinement across five pediatric oncology clinics. Improvements were based on feedback from focus groups, surveys, and written suggestions. The interdisciplinary research team collaborated with healthcare professionals (HCPs) as coresearchers to ensure practical applicability, acceptance, and user-centered design. Results: The OKRA-Compass provides a structured but flexible framework for BBN in pediatric oncology, comprising a comprehensive guidebook, pocket guide, and checklists. Its application improved team preparation, communication style, and role clarity during emotionally demanding encounters. Conclusion: The structured framework of the OKRA-Compass aligns theoretical foundations with clinical practice. Its participatory development process fostered collaboration and ownership among HCPs, making it a valuable resource for improving communication in pediatric oncology. Practice implications: Integrating the OKRA-Compass into training programs and clinical routines may promote empathic, patient-centered care. We recommend interprofessional training to further support its application and dissemination.