This paper considers the role of economics in abuse of dominance cases. Economic analysis and evidence has become increasingly important in the context of effects-based approaches to assessing possible abuse of a dominant position. The paper sets out the core economic framework for assessment of abuse of dominance including the balancing of over- and under- enforcement and the relevance of the characteristics of the markets and economies in question. It comments, in particular, on the challenges faced by authorities in developing and middle-income countries given the rapid expansion of competition law in these jurisdictions. The economic tests in different types of exclusionary and exploitative abuses of dominance are considered along with the practical challenges in the gathering of evidence and undertaking appropriate assessments. The role of economists in cases, including as experts providing testimony on the part of private parties, is examined. This paper was prepared as a background note for a discussion on Economic Analysis and Evidence in Abuse Cases held at the 2021 OECD Global Forum on Competition.