Increasing awareness of the importance of ecological and social aspects of effects of business operations has led to a growing interest in sustainability. To this end, many firms are adopting supply chain management practices that are expected to foster sustainability along their supply chains. This research studies the effect of drivers on adoption of sustainable supply chain management (SSCM) practices and impact of this adoption on the performance of a firm. Effect of size on the latter impact is also studied. For this, we follow Elkington's (1997, 1999, 2006) triple bottom line model of a firm's sustainability comprising of economic, environmental and social aspects. After an exhaustive literature review, the hypotheses proposed in this study were tested by an empirical study. Survey data was gathered and analyzed using multiple regression analysis and structural equation modeling. The results of this study provide substantial insights into the effects of SSCM practices and their relation to firm performance.