High Performance Work Systems (HPWS),as a set of inter-related and interdependent HR practices, have been considered to have significant impact on firm performance, according to past literature in Strategic Human Resource Management. In the Indian context, the nature of this relationship has not been explored thoroughly so far, keeping in mind the numerous contextual and intervening variables present in the entire process. In this study, the author has collected data from more than 200 organizations and 600 employees spanning across the Indian service sector and analysed the data to explore multiple hypotheses. The findings provide some important insights about the effectiveness of HPWS and its different components on operational and financial performance of firms. It also offers ideas about the role of selected variables in the HPWS-Firm Performance process. These can provide critical guidelines for HR practitioners and at the same time, add significantly to related area of research.