High-performance work systems (HPWSs) have been a topic of debate due to the complicated links transforming human resource management (HRM) practices into valuable outcomes for both organizations and their employees. However, the complexity of these links between HPWS practices and outcomes has resulted in many incremental theoretical steps, one of which is to shed further light on the “black-box” of HRM – outcomes links. The black-box refers to the inadequate knowledge of issues; for example, how and when certain bundles of HPWS practices result in particular outcomes and why HPWSs do not always produce positive results. Hence, engaging with the “rhetoric” versus “reality” debate in HPWS literature, the current research comprises two studies, utilizing both qualitative and quantitative studies in an attempt to explore the HPWS black-box and contribute to the understanding of HPWS theory and literature. Equally as important and not adequately understood is the concept of HRM philosophy as an important component to understand what drives the HPWS infrastructure in an organization. HRM philosophy has been considered the driving force behind the implementation of HRM policies, signaling management’s intentions to employees. A well-defined HRM philosophy guides policymakers to craft successful HR goals; however, there have been few explicit studies of HRM philosophy in the HPWS context. This research begins with a qualitative study within three Pakistani telecommunication organizations to understand the way different HRM philosophies may drive different forms of HPWS, and consequently, different outcomes. Furthermore, this research draws on the theoretical notion of HRM system strength to further illuminate questions relating to the black-box. HRM strength is referred to as the consistent, distinct, and consensual implementation of HRM practices. Employees’ understanding of HRM processes and HPWS initiatives undertaken by managers is critical to the successful implementation of HPWS. Employees are the ultimate recipients of HPWS practices, and their perceptions of these practices have received substantial scholarly attention. Thus, this research incorporates employee awareness of and satisfaction with these HPWS policies as important variables of the HPWS black-box phenomenon. Employee attribution of HPWS policies is another important component of the HPWS model of this research, motivated by the fact that employee ratings of HPWS policies add to the success or failure of a HPWS. It is important to recognize that previous literature has demonstrated that HPWSs can have positive outcomes for organizations while having a negative effect on employees. Hence, this research was designed to ensure that the outcomes for multiple stakeholders were considered. The outcome variables of this research therefore include employee emotional exhaustion as an indicator of employee wellbeing at work, organizational citizenship behaviors (OCB) as a measure for organizational benefit; and employee customer service measured as a proxy for customer service outcomes. Furthermore, the current research investigates HPWS implementation among three telecommunication organizations from Pakistan. Contextual factors and unique organizational HRM approaches cannot be overlooked in management studies. Pakistan is a developing economy with an organizational history of directive management styles, and HRM researchers have observed that these organizations have begun to implement sophisticated HPWS policies. Pakistan is a context embedded with strong national culture and Islamic values. However, transitions have been observed in the management styles of Pakistani organizations. Thus, Pakistani organizations, being exposed to simultaneous forces of convergence and divergence, propose Pakistan as an under-researched and possible avenue to explore HPWS. This research was driven by two overarching research questions: How does HRM philosophy influence the adoption and implementation of HPWSs in telecommunication organizations in Pakistan? and How do the HPWS practices influence employee outcomes through the black-box in telecommunication organizations in Pakistan? To further guide this research, these research questions were divided between two studies. The first research question was explored as a part of qualitative Study 1, where HRM philosophy was examined through interviews with participating organizations; while the second research question was explored as a part of quantitative Study 2, where elements of the HPWS black-box were hypothesized and statistically analyzed. Overall, an inductive-deductive exploratory research technique was applied with 55 interviews and 537 questionnaires from senior managers, HR managers, and employees. The key findings of the thesis revolve around the role of HRM philosophy, HRM system strength, and employees’ understanding of HPWS practices in the HPWS process. Findings indicate that HRM philosophy ensures vision and clarity for HPWS purpose not only for managers, but also allow them to share a salient HPWS purpose throughout the organizational levels. Additionally, following the HRM process approach, HPWS implementation with strong philosophical foundations are likely to enhance the employees’ awareness and satisfaction with HPWS and these improved employees’ perceptions generate positive employees’ reactions such as reduced emotional exhaustion, OCB, and customer service. The findings also support the conditional effects of HRM strength and employees’ attributions of HPWS practices. The findings suggest that HPWS can result into promising outcomes if they are supported by an HRM philosophy and their purpose is equally communicated with the employees. Not the presence of HPWS practices, but their right implementation and acknowledgment by the employees can make a difference to generate desired outcomes. This research contributes to the theories presented by P. Wright and Nishii (2007) and Kepes and Delery (2007) on shared HRM perceptions and employees HRM experiences, because in this research, employee awareness and satisfaction with the HPWS policies were found to actively enhance the effect of HPWS on employee wellbeing, OCB, and customer service. Moreover, the results also support Bowen and Ostroff’s (2004) theoretical proposition that consistency, distinctiveness, and consensus in HRM practices is critical to creating strong HRM structures. The study’s implications are for both managers and theory. As the findings observed a positive role of HRM philosophy in managers’ decisions to choose and implement a more purposeful and salient HPWS, it is important for managers to invest in the formulating a well-guided HRM philosophy and purpose to orient their HPWS decision at the workplace. Moreover, employee-centred HRM philosophies and HPWS processes considering employees as organizational assets can generate desired outcomes at greater lengths. Employees’ acknowledgement of managers’ efforts of HPWS practices increase chances for managers to build string employment relationships with employees. In theory, insights are for researchers and reviewers to conduct more research by linking HRM philosophy with the use of HPWS practices because philosophies represented the knowledge, assumptions, and expectations about the HR systems; thus, providing a better understanding of HPWS implementation. Additionally, it is also important to study the employees’ acknowledgement of actual HPWS practices as a part of ‘HRM process theory’ to investigate the impact of HPWS practices on the outcomes.