This research was directed by four primary objectives. This study aimed to analyse the impact of institutional culture on employee retention within private universities in Kenya. The second aimed to evaluate the moderating effect of mental health on the relationship between institutional culture and employee retention. The third objective was to determine the moderating effect of work-life balance on employee retention. The study aimed to investigate the combined impact of institutional culture, mental health, and work-life balance on employee retention in these institutions. Job Demands–Resources (JD–R) Theory and the Social Exchange Theory were utilized to explain the phenomena. The study utilised both qualitative and quantitative methods for data collection. This study employed a pragmatic research approach, emphasizing that the significance of inquiry is rooted in its practical outcomes and applicability in real-world contexts. This research, adhering to the stated philosophy, did not include the collection of primary data. The study utilised solely secondary data sourced from existing empirical studies, policy documents, scholarly journals, and institutional reports pertaining to private universities in Kenya. The emphasis was on synthesising evidence concerning institutional culture, mental health, work-life balance, and employee retention. These factors are essential for comprehending productivity in higher education institutions. Secondary sources were systematically identified and reviewed through academic databases and digital libraries, ensuring a diverse array of peer-reviewed materials that provided both theoretical and contextual insights. The analysis employed thematic content analysis, facilitating the identification of recurring patterns, relationships, and gaps in the literature. Themes were analysed in relation to the research objectives to derive conclusions and develop evidence-based recommendations. This methodology is consistent with the pragmatic paradigm, focussing on actionable knowledge obtained from credible, context-specific sources instead of abstract theorisation or direct fieldwork. The results indicated that institutional culture significantly and positively impacted employee retention. Universities characterised by inclusive, transparent, and participatory cultures exhibited reduced turnover intentions among staff. Mental health significantly moderates employee commitment and productivity. Access to psychological support services and wellness programs enhances these outcomes, even in institutions with moderate ratings of institutional culture. Work-life balance emerged as a significant factor, moderating the effects of institutional demands and stressors on retention. Employees who indicated flexible work schedules and support for family or personal commitments demonstrated increased job satisfaction and organisational loyalty. Institutional culture, mental health, and work-life balance collectively explained a significant portion of the variance in employee retention rates. The analysis indicated that these variables interacted in complex yet complementary manners, underscoring the necessity for an integrated approach to human resource management in private universities. The research findings indicate that private universities in Kenya should emphasise employee well-being, foster organisational inclusivity, and implement flexible work policies to enhance staff retention and, consequently, institutional productivity. University leadership should invest in formal mental health programs, cultivate supportive workplace cultures, and implement work-life policies that address the diverse needs of academic and administrative staff. Future research should investigate the longitudinal effects of these factors on institutional performance and broaden the scope to include public universities for comparative analysis. Institutional culture significantly influences mental health, work-life balance, employee retention, and overall institutional productivity.