Objective: To determine the competencies of charge nurses. Methods: The systematic review and thematic synthesis study was done at Iran from 1 Apr 2018 to 31 Jul 2018. Five electronic bibliographic database (Science Direct, Pro Quest, Scopus, Pub-Med, Scientific Information Database) were systematically searched for relevant literature published from 1980 to 2018. Content analysis was done to categorise competency of charge nurses. Results: Of the 1285 articles, 24(1.86%) were reviewed. Through thematic synthesis, six themes identified were self-management, others' management, clinical competency, conceptual-cognitive competency, professional-legal competency and competency in communication. There is need to improve knowledge and skills in the domains of management, leadership, communication and perceptual/cognitive competency. Conclusion: The findings may help nurse administrators and nurse directors in designing training programmes for charge nurses who could improve their competencies.