Investors, stock exchanges and financial regulatory institutions can be used as strong levers for making firms accountable for achieving sustainable operational performance and not just maximizing profits. The objective of this research study is to enhance the quantitative tools available to stakeholders for evaluating relative operational performance of firms, thereby encouraging the financial investors to base their portfolio investment decisions on the basis of sustainable operational performance of firms. The study reviews the existing literature on evaluating relative operational performance of firms on sustainability metrics and proposes multi-level multi criteria decision making (MCDM) quantitative methods for measuring the same. The research work demonstrates the research framework proposed in the study by evaluating the 2014 Sustainable Operational Performance of firms in the oil & gas sector. The reason for choosing the oil & gas sector for this case study is in view of the relative large ecological and social impact which this industry has on different stakeholders. Due to the same reasons, the oil & gas sector is a bit more advanced in terms of its sustainability performance reporting standards. The review of past literature and the sustainability reports of firms for the year 2014 is initially used to develop the construct for measuring the firm operational performance on three pillars of TBL i.e. for the ecological, social and economic dimensions.