This systematic literature review examines the determinants of employee retention across multiple sectors, focusing on the roles of leadership, work environment, and employee engagement. Employee retention is a critical challenge faced by organizations worldwide, affecting various industries such as healthcare, education, hospitality, and business services. The problem addressed in this study is the lack of a unified understanding of the key factors that drive employee retention in these diverse sectors. The methodology involved an extensive search using the Scopus database, applying strict inclusion and exclusion criteria to ensure the relevance and quality of the studies. The review encompasses a total of 42 primary studies, which were systematically analyzed to identify the key determinants of employee retention. To achieve this, we conducted an extensive search of scholarly articles from reputable databases such as Scopus focusing on studies published between 2019 and 2024. The methodology adhered to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, ensuring rigor and transparency. The finding was divided into three themes which is (1) leadership and retention strategies, (2) employee engagement, motivation, and job satisfaction and (3) generational, sector, and theoretical perspectives on retention. The findings reveal that leadership styles, particularly servant and transformational leadership, significantly influence retention by fostering strong employee engagement and job satisfaction. Work environment factors, such as compensation, work-life balance, and organizational culture, were also found to play critical roles in reducing turnover. Additionally, employee engagement emerged as a key mediator in the relationship between leadership and retention, emphasizing the need for organizations to invest in both leadership development and employee well-being. The review concludes that a holistic approach, integrating leadership practices, supportive work environments, and engagement strategies, is essential for improving retention across various sectors. Further research is suggested to explore the contextual differences in these factors across industries and regions to provide more tailored recommendations for organizations.