How trust shapes the relationship between employee engagement and organizational citizenship behavior: evidence from Saudi Arabia's private healthcare sector

Employee engagement is known to influence OCB, yet the multilevel trust mechanisms underlying this relationship, particularly in healthcare contexts, remain underexplored. This study examines the direct, parallel, and serial mediating effects of supervisor trust and organizational trust in the link between employee engagement and OCB in Saudi Arabia's private healthcare sector. Grounded in Social Exchange Theory, Leader—Member Exchange Theory, and Trust Transfer Theory, the study tests a conceptual model using PLS-SEM based on a survey of 232 healthcare employees. The findings indicate that employee engagement positively influences OCB both directly and indirectly through supervisor trust and organizational trust. Supervisor trust also has a significant positive effect on organizational trust, reflecting a cascading trust transfer. The model explains 54.5% of the variance in OCB, demonstrating strong explanatory power. The study extends the organizational behavior literature by integrating multilevel trust processes within a single framework that links engagement to discretionary workplace behaviors. The findings offer evidence-based recommendations to strengthen leadership, trust, and employee engagement to improve workforce performance and service excellence within Saudi Arabia's Vision 2030 healthcare transformation agenda.