Background: Pediatric oncology nursing involves complex clinical and emotional care, yet many nurses feel unprepared for its demands. Simulation-based education offers experiential training to enhance clinical skills and emotional readiness. This systematic review aims to evaluate the effectiveness of simulation-based educational interventions in enhancing the clinical competencies of pediatric oncology nurses. Methods: A comprehensive search was conducted in six databases: PubMed, Web of Science, Cochrane, MEDLINE, CINAHL, and Scopus. The inclusion criteria comprised empirical studies involving simulation-based training targeting pediatric oncology care competencies. The study follows the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. Methodological quality was assessed using the Standardized Quality Assessment Criteria. Results: Eight studies published between 2007 and 2024 were included in the review. Simulation-based interventions improved nurses’ confidence, self-efficacy, communication, and adherence to chemotherapy safety protocols. High-fidelity simulations were the most frequently used method. Hybrid simulations incorporating storytelling and video feedback promoted team-based learning and empathy. Most studies demonstrated moderate to high methodological quality. Conclusion: Simulation-based education enhances clinical competencies in pediatric oncology nursing, particularly in preparing nurses for oncologic emergencies, procedural pain, and end-of-life care. Despite promising results, methodological heterogeneity and the predominance of short-term outcome evaluations limit the generalizability of findings. Standardized simulation frameworks and long-term assessments are recommended to strengthen evidence-based nursing education. Implication to practice: Simulation-based education enhances core competencies in pediatric oncology nursing and should be integrated into education. Standardized frameworks and longitudinal evaluations can strengthen its evidence-based practice.