Background/Objectives: Nurse retention remains a major global challenge for healthcare systems, intensified by workforce aging, rising care complexity, and the long-term impact of the COVID-19 pandemic. Despite extensive research, the evidence on nurse retention remains fragmented and frequently focuses on isolated determinants. This review aimed to synthesize the multifactorial determinants of nurse retention by integrating organizational, relational, and individual perspectives. Methods: An integrative review was conducted following Whittemore and Knafl’s approach and reported according to PRISMA 2020 guidelines where applicable. A systematic search of six databases identified studies published between 2016 and 2026 addressing nurse retention in hospital settings. Included studies underwent methodological quality appraisal using validated tools, and findings were synthesized narratively. Results: Twenty-five articles were included. The analysis revealed differences in perspective between nurse managers and nurses regarding the factors that influence retention. Transformational and participative leadership among nurse managers enhanced staff retention through supportive organizational climates and higher professional commitment. For staff nurses, positive work environments, collegial support, and psychological resources such as self-efficacy and resilience were key predictors of intention to stay. These findings can be interpreted through Herzberg’s Two-Factor Theory, Self-Determination Theory and Theory of Planned Behavior, which collectively highlight how recognition, autonomy, and competence satisfaction drive nurses’ intention to remain in their roles. Conclusions: Nurse retention reflects dynamic, multilevel processes rather than the influence of single determinants. Integrated, theory-informed approaches targeting organizational structures, relational climates, and individual psychological resources are required to strengthen workforce sustainability and support high-quality care delivery.