PurposeThe study investigates the effects of core self-evaluations on project managers' competencies. The study further examines the moderating effect of cultural intelligence between core self-evaluations and competencies.Design/methodology/approachIn this study, with a descriptive-survey approach, necessary data were collected from a sample of project managers of Iran's Ministry of Communication and Information Technology through questionnaires. The conceptual framework of the study was tested according to structural equation modeling by PLS software.FindingsFindings show that core self-evaluations have positive and significant effects on project managers' competencies among which psychological stability has the greatest effect. Furthermore, the moderating role of cultural intelligence in the relationship between core self-evaluations and project managers' competencies was confirmed. According to the calculated coefficient, motivational cultural intelligence had the greatest role.Research limitations/implicationsThe data were collected using a questionnaire at a single point in time, and thus, not allowing cause–effect inferences. Also, the demographic variables were not controlled.Practical implicationsThe results of this study provide some implications for HRM professionals and project managers interested in promoting a system of HR practices that contributes to enhancing project managers' competencies and effectiveness.Originality/valueThis study advances our understanding of the factors that have an effect on project managers' competencies, specifically on a list of main competencies necessary for project managers' performance. Moreover, it suggests that project managers' competencies will benefit from cultural intelligence, which will display a greater effect when embedded in highly diverse cultural contexts.