Purpose: This paper aims to investigate mediating effects of employees' work engagement in the relationships between their personal resources (i.e. self-efficacy, organizational-based self-esteem and optimism) and turnover intention within Korean organizations. Design/methodology/approach: A total of 571 survey responses collected from Korean organizations were utilized and analyzed to test the proposed research hypotheses by using structural equation modeling. Findings: The results showed that all of personal resources had a positive impact on work engagement and work engagement had a negative impact on turnover intention. The results also revealed that although both organizational-based self-esteem and optimism had a negative impact on turnover intention, self-efficacy had an impact on turnover intention with the opposite way. In addition, work engagement mediated the relationships among self-efficacy, organizational-based self-esteem, optimism and turnover intention. Practical implications: The findings of the study could suggest practical implications when human resource development (HRD) professionals consider appropriate human resource interventions (e.g. training intervention) as to how to create and maintain a working environment where employees are facilitated and learned to have high levels of personal resources (i.e. self-efficacy, organizational-based self-esteem and optimism), which leads to enhancing employees' work engagement and positive outcomes (e.g. lower turnover intention). Originality/value: Given that little research effort has been made to investigate the relationships among personal resources (i.e. self-efficacy, organizational-based self-esteem and optimism), work engagement and turnover intention, this research contributes to the HRD literature by adding empirical evidence of the relationships in the context of Korean organizations.