Interdepartmental collaboration has emerged as a critical strategic approach for addressing the increasing complexity, fragmentation, and performance demands of modern healthcare systems. As patient care pathways span multiple clinical, diagnostic, and administrative units, effective cooperation among medical departments is essential for delivering coordinated, high-quality, and patient-centered care. This review aims to synthesize current evidence on the impact of interdepartmental collaboration on patient outcomes, care quality, and organizational performance within healthcare settings. Drawing on findings from empirical studies, systematic reviews, and conceptual frameworks published in recent years, the review examines patterns of collaboration across departments, key enabling mechanisms, and reported outcomes at both patient and system levels. The evidence indicates that strong interdepartmental collaboration is consistently associated with improved patient safety, reduced medical errors, enhanced continuity of care, and higher patient satisfaction. At the organizational level, collaboration contributes to workflow efficiency, better resource utilization, workforce engagement, and overall system resilience. Despite these benefits, persistent barriers such as professional silos, communication challenges, and organizational culture constraints remain. This review highlights the need for integrated governance structures, supportive leadership, and digital enablers to sustain effective collaboration and optimize healthcare system performance.