Purpose: This paper explored the direct and indirect effects of demographic diversity variables on citizenship behaviours, affective commitment, collective efficacy and general productivity. Design/Methodology/Approach: A self-report questionnaire was used to gather data from employees in the public sector (local government) of Australia. Findings: Results of the hierarchical regression analyses showed direct and significant relationships between certain demographic diversity variables and several criterion variables. Moving from non-management to management level was predictive of an increase in organisational citizenship behaviours and affective commitment. Additionally, an increase in tenure within a work unit was predictive of general productivity. Conversely, an increase in organisational tenure was predictive of a decrease in general productivity. Also, an increase in women in a work unit was predictive of a decrease in organisational citizenship behaviours, collective efficacy beliefs and general productivity. Furthermore, an increase in men in a work unit was predictive of a decrease in organisational citizenship behaviours, collective efficacy beliefs and general productivity. Moderated regression analyses indicated that transformational leadership moderated relationships between organisational tenure and organisational citizenship behaviours as well as organisational tenure and general productivity. Finally, transformational leadership moderated relationships between women in work unit and organisational citizenship behaviours, and women in work unit and general productivity. Research limitations: We gathered cross-sectional data for our research while both of our leadership and performance data were based on participants’ self-reports. Future research should gather data from multiple sources and employ longitudinal and experimental designs to explore the link between demographic diversity, leadership and organisational outcomes. Practical implications: Based on the current results, managers need to understand and nurture task related demographic diversity (such as gender composition of a workgroup, non-management vs management level, and tenure in work unit) shown to be positively related to citizenship behaviours, affective commitment and general productivity. Furthermore, organisations should put in place human resource management programs which actively promote transformational leadership in order to lessen or neutralise possible negative effects of demographic diversity on relevant organisational outcomes. Originality/value: This empirical study adds to the growing research findings regarding the relationship between demographic diversity variables and various organisational outcomes using data from the public sector of Australia.