Using a cross-sectional design to evaluate the perceptions of 242 nurses working in a Malaysian hospital, this study investigates the mediating role of work locus of control (WLOC) on the relationship among emotional intelligence (EI), organisational citizenship behaviours (OCBs), and mental health among nurses. Additionally, the role of EI is examined. Findings indicate that EI correlates positively with OCBs and negatively with mental health and that WLOC mediates the relationship between EI and OCBs. However, WLOC does not mediate the relationship between EI and mental health. An in-depth understanding of nurses' EI provides insights into health institution management to increase organisational outcomes. Results of this study are interpreted to indicate that EI should be part of nurse training and that OCBs are associated with performance and productivity. It is suggested that EI could also be included in selection processes to encourage growth and development of a health institution.