Modern competition law regimes promote economic goals such as consumer welfare and efficiency. Therefore, competition law is intrinsically linked with the discipline of economics. Relevance of economic theory for competition law is evident with the incorporation of economic concepts and reasoning into case analysis, growing judicial reliance on economic evidence and substantial presence of economists in competition authorities. Economic theory provides frameworks to comprehend theory of harm and for analysing information regarding: (i) structure of an industry; (ii) strategies adopted by firms and (iii) demand conditions and the underlying technologies. Competition economics, an applied field of modern Industrial Organisation (IO) theory provides blueprints for evaluating the likely effects of conduct falling in the purview of antitrust laws and futuristic assessment of mergers.