Studies of the evolution of human resource management (HRM) within Western contexts of industrial changes and economic developments have revealed particular nuances and idiosyncrasies in the transformation of the HR department's roles and status. However, little research has been done to systematically examine the current state of HRM in developing economies. Simultaneously, little has been written about the determinants and contribution of HR department effectiveness in developing settings. The current thesis bridged these research gaps through the four related studies. Study 1 utilised an institutional lens to conduct a content analysis approach to examine the development of HRM in Vietnam. Leximancer technique was used to analyse a collection of 100 published journal articles on HRM in Vietnam from 1983 to 2013. The contribution of Study 1 is a systematic and semantic understanding of HRM development in Vietnam which has not been examined previously. The findings showed that the development of HRM in Vietnam has been associated with key stages of economic development. Study 1 also showed the integration of personnel management, HRM, and SHRM in Vietnam. Findings in Study 1 played a fundamental role in examining antecedents and consequences of the HR department's effectiveness in response to the scarcity of research on this topic in Western and Vietnamese literature. Study 2 was based on the existing literature pertaining to power and influence of the HR department and institutional theory in human resources. Study 2 examined the impact of formal authority on the perceptions of HR department effectiveness. Study 2 obtained a sample of 405 line managers' responses and a separate sample of 155 line managers to test and validate the proposed model. Structural equation modelling (SEM) and multiple linear regressions were utilised to analyse the data. Multiple group analysis in SEM was also undertaken. Study 2 contributed empirical evidence to the literature by showing that formal authority is an important condition for the HR department to be recognised as effective in Vietnam's public sector organisations. Thus, the public sector HR department needs to consider political and influencing skills to increase its impact. By contrast, Study 2 also found that the absence of the HR department's formal authority in Vietnam's private sector organisations highlights its ability to develop a partnership with line managers and transfer HRM activities to these counterparts. Study 3 extended the perspective of power and influence of the HR department to examine the effect of an organisation's HR orientations on the implementation of HRM. Two separate samples of 405 and 192 line managers were used to test and confirm the research findings. SEM and partial least squares were employed in the analysis. Study 3 added to the perspective of a strong HRM system by providing empirical evidence of the consistency of an organisation's HR emphasis with strategic HRM orientation and implemented HR practices. This consistency affected line managers' perceptions of HR department effectiveness. Multiple group analysis affirmed that ownership types have significant influences on HRM implementation and HR department effectiveness. Study 4 investigated the impact of an organisation's strategic orientations on the roles and status of the HR department. SEM was used to test the hypothesised model with a sample of 484 line managers. Study 4 highlighted the importance of strategic orientations in influencing line managers' perceptions of HR department effectiveness. Importantly, when the HR department does not perform effectively its HR roles, strategic orientations are a means for the HR department to enhance its effectiveness. Study 4 also found that line managers hold positive perceptions of the strategic contribution of the HR department. This is opposite to findings of prior studies, and so this study makes a significant contribution to Vietnamese literature on HRM.