While a considerable body of research on the effects of high performance work practices (HPWPs) on organizational performance exists, we know only little about the factors that condition their implementation. Among the few studies that have been conducted on this topic, two perspectives can be identified. The first suggests that HPWPs implementation depends on decision making in organizations and the role of managers in executing those decisions. A second perspective attributes variation to contextual factors, such as the comparative institutional context or the industry the organization operates in. This dissertation adds to our knowledge about the implementation of HPWPs as it considers both contextual and intra-organizational factors. The first study draws on a political perspective to address how the influence of the HR function on the organization’s strategic decision making relates to HPWPs implementation. The second study examines the effects of HPWPs implementation in the context of organizational change and finds a moderating effect on the association between perceived organizational change intensity and voluntary employee turnover. Finally, in the third study I use multi-level analysis of ratings of HPWPs implementation, and simultaneously test the effects of comparative institutional context, industry, organization and rater characteristics on individual-level ratings of HPWPs implementation.